Utility of Red Lines in U.S. Foreign Policy


Red lines have been used sporadically and in a haphazard manner in U.S. foreign policy in recent decades, rendering them to be of dubious value.

This informal paper attempts to clarify the nature of red lines and how the can best be used or shouldn’t be used, exploring questions such as:

  • When are red lines appropriate?
  • When are they inappropriate?
  • How should they be used?
  • How should they not be used?
  • Are they ever appropriate?
  • Should they only be used as a last resort?
  • Should they be used more often?
  • What is their impact on world affairs, society, and life in general?

Caveat / Scope

The term red line has been used in a number of contexts over the years. The intention of this informal paper is to focus on the conduct of U.S. foreign policy only. Other traditional meanings of red lines, none of which is covered in this paper are:

  • Redlining — refusing loan, mortgage, insurance, or any other service due to a high-risk area, typically of a racial or socioeconomic nature. Also encompasses refusal of services on a racial or socioeconomic basis as a means to exclude the affected groups.
  • Political behavior within a country.
  • Incitement at a social level within a country.
  • At a personal level as a defense and deterrent against personal attack.
  • Scientific and ethical conduct, such as human experimentation and restrictions on embryo experiments.
  • Religious tolerance.
  • Traditional military meaning of the front line where battle is occurring and blood is actually being shed, as in the proverbial thin red line where a small force is holding firm against the attempted advance of a superior force.

Not that they are not important areas in their own right, but simply that they are out of scope of a paper on foreign policy.


A red line is used to maintain order or establish a new order according to certain technical criteria by establishing that severe consequences will result if the technical criteria are not maintained or achieved in some specified manner or in some specified timeframe.

A red line may be used to maintain the status quo to prevent a negative change, or to cause a positive change from a negative status quo that will result in a new status quo that is considered more acceptable. The former could be termed a proscriptive red line, the latter a prescriptive red line.

A red line is triggered by some highly undesired prospect or imbalance of power, or by some highly undesired existing condition which needs to be remedied to restore a desirable balance of power.


A red line is either a threshold of undesired behavior by an adversary with severe consequences if the threshold is exceeded (a proscriptive red line), or a threshold of required behavior with severe consequences if the threshold is not met (a prescriptive red line.) The most common usage is the former, a proscriptive red line, as a warning to the adversary not to engage in the specified conduct.

There are various formulations or characterizations of red lines:

  • A threshold which may not be crossed without severe consequences.
  • A threshold which must be met to avoid severe consequences.
  • A line in the sand.
  • A line which must not be crossed.
  • A line which no one should cross.
  • A line which when crossed demands action.
  • Point of no return.
  • No-go zone.
  • Don’t go there.
  • A non-negotiable demand.

Historical use of red lines

A detailed or even summarized cataloguing of past use of red lines is beyond the scope of this informal paper.

Foreign policy vs. foreign relations

Foreign policy and foreign relations are two sides of the same coin. Foreign policy is the conceptualization and formalization of policy, while foreign relations is the actual conduct of relations with other countries. Policy is theory, relations is practice. Foreign relations is foreign policy in action.

In the case of red lines, foreign policy is concerned with deliberations, development, and decision-making on the use of a red line in policy. Foreign relations would be concerned with implementing that red line policy, publicly announcing it, communicating with allies and the media, and even communicating with the target adversary, as well as monitoring the threshold for the red line, and managing the consequences if the red line is crossed.

Foreign relations vs. international relations

Foreign relations and international relations are also two sides of the same coin. Foreign relations is how a country thinks about the rest of the world and how that country discusses the rest of the world within the country, while international relations is how the country actually discusses international matters with the rest of the world.

In the case of red lines, foreign relations would include both the development of the red line policy as well as discussions and planning for how to announce and implement the policy. International relations would be the actual announcement and subsequent communications and interactions with all relevant international parties, both allies and adversaries, as well as international organizations.

Foreign relations would also include interactions with domestic oversight, such as congressional committees, as well as communicating with the media.

The adversary

From the perspective of a given country, such as the U.S., the remaining countries of the world can be categorized as friends, allies, neutral, unfriendly, or adversaries. An adversary is another country which is either engaging in behavior or policies which are harming or have the potential to harm the interests or the first country, domestic or around the world, or is refusing to to engage in behavior or policies which are needed to assure that the interests of the first country are not at risk of harm in the future.

Benefits of red lines

The primary benefit of a red line is as a deterrent, a big stick, which causes the adversary to behave as desired.

A secondary benefit is to incentivize change to remedy a very adverse situation, more of a carrot, which offers a pullback from the strained relations of the elevated confrontation that is leading to the red line policy in the first place.

Another key benefit of a red line is to introduce some sense of certainty into an uncertain or adverse situation.

A red line can also lower the sociopolitical anxiety level based on an expectation that the severity of the consequences of crossing the red line will be an effective deterrent, decreasing the anxiety that would have come if the adverse activity had occurred absent the red line.

The theory is that the anxiety associated with the adversary getting away with the targeted bad behavior is significantly greater than the anxiety associated with the prospect of the red line consequences triggered by the red line.

Downsides of red lines

The primary downside of a red line is the loss of flexibility.

A red line also raises the sociopolitical anxiety level based on an expectation or possibility of the consequences of the red line being crossed.

A red line is very bad advertising, informing the adversary that behavior anywhere up to but just short of the red line is okay, enabling and even encouraging bad behavior in the safe zone short of the red line. This gives adversaries a target or button to push to cause the country to experience heightened anxiety. It also suggests to the whole world that the adversary is much more important than they might actually be.

Another important downside of red lines is the high risk of loss of credibility should the red line be crossed without incurring the promised severe consequences in a very prompt manner.

Finally, the declaration of a red line may offend or challenge the adversary to such an extent that they are emboldened to continue the undesired behavior and maybe even take it a step further just to overcome the perceived insult.

Value of credibility

It can be quite easy and very emotionally satisfying to throw down the gauntlet of a red line, but this has a very high risk to credibility, both in terms of whether officials are too prone to being baited into knee-jerk reaction and whether their promise of severe consequences is credible. And when the red line is actually crossed, any hesitation or walking back from promised consequences will be a severe blow to credibility.

The problems with credibility are that it is too difficult to build and too easy to squander, and extremely difficult and time consuming if not impossible to rebuild after squandering.

Sense of commitment

In addition to the publicly perceived credibility of the commitment behind a red line, there has to be a true sense of private and even personal commitment behind the public commitment. It is not enough to simply talk tough — officials need to be passionately committed in their own minds. The public commitment has to match their true intentions.

Deterrent value

The primary intent of drawing a red line is as a deterrent to some unacceptable situation, action, or behavior.

But, the deterrent value of a red line is dubious at best. More properly managing the international environment well in advance of any violation is a much more effective deterrent.

In practice, a red line may be little more than a warning of action in response to an expected violation.

In addition, the loss of flexibility imposed by a fixed red line can cost more than the limited value received from any actual deterrent effect.

Adversary domestic pressures

One particularly thorny problem with red lines is that even if the leaders of the adversary really do see the need to bow to the red line, they may be under too-intense domestic pressure to do so.

There may be issues of ego and honor at stake as well, so that even an otherwise rational leader of an adversary may feel compelled to go down with the ship rather than surrender to a foreign power.

These factors must be taken into account when contemplating and analyzing a proposed red line policy.

Costs of hesitant response to red line violation

A significant degree of comfort may be derived from the act of drawing of a red line, but that psychological boost can be very short-lived, especially if any response to a violation of the red line is not swift, steady, and severe.

Failure to field a robust and prompt response to a violation will incur significant, possibly irreparable loss of credibility, and may have the side effect of enabling and encouraging future violations by the targeted adversary or other potential adversaries.

Undermining the confidence of allies can in itself be very consequential for future international confrontations or even less-confrontational situations where mere cooperation is needed.

Tool of last resort

A red line should be considered only as a last resort, after all other viable alternatives have been exhausted.

Too many active red line policies can make management of overall foreign policy very difficult.

Inadvertent violations

It is very possible that an adversary might inadvertently violate a red line, not in some egregious and obvious manner, but more as a technical violation, possibly even by accident, or there may be some ambiguity or uncertainty about the actual violation. The question is what response would be reasonable in such a scenario. On the one hand, a cautious, temperate response might seem laudable, but any tentativeness could also signal weakness and undermine the credibility of the red line.

A grace period of some sort might be advisable, not that a violation should go completely unanswered, but that a very stern last-chance warning should be issued, such that if the adversary doesn’t withdraw the violation in very, very short order, the full consequences will follow.

The question is how long such a grace period can be. If too short it is meaningless, but if too long it gives the adversary some wiggle room to test the resolve of the red line arbiter. Nonetheless, anybody drawing a red line has to carefully and clearly consider in advance the protocol for how an inadvertent violation would be dealt with.

In classic terms, some sort of warning shot must be fired to both give the adversary a chance to correct any honest or innocent mistake and to confirm the resolve of the country implementing the red line.

In some cases a grace period might be a few minutes or even a few hours, while in other cases it might be days or weeks with some sort of administrative appeal before consequences proceed.

All of this complexity of course argues against the use of red lines in the first place.

Red line as a requirement

A typical, proscriptive red line requires that an adversary refrain from engaging in undesired behavior, but a prescriptive red line can be used to establish a positive action as a requirement to be met by the adversary, such as:

  • Conditions that must continue to be met that an adversary is at risk of discontinuing.
  • Conditions that are not yet met but which the adversary is being strongly encouraged to meet.

For example, an adversary may be encouraged to participate in some international treaty or admit inspectors of some sort.

A negotiation ploy?

How real is a purported red line? Is it really real, or simply a negotiating ploy with no intention or prospect or belief that it will be reached? The hope or intent may be that the raw threat of severe consequences will cause the adversary to back down, with no expectation of actually crossing the red line. But, the adversary might place such a high value on engaging in the activity that crosses the red line that they are willing to bear the costs of the severe consequences, such that they remain undeterred by the red line.

The country drawing the red line will then be faced with several prospects:

  1. Seeing the negotiating ploy fail.
  2. Suffering from loss of face from failing to follow through with the promised severe consequences.
  3. Suffering from any blowback from following through with the promised severe consequences which they honestly had no intention of following through on in the first place.
  4. Seeing the adversary prevail beyond the red line, undeterred, and unbowed by the actual consequences, if any.

In short, use of a red line as a negotiating ploy is a high-risk proposition.

Can’t bluff

Bluffing with a red line is not advised. Sure, a country can bluff and maybe it might work, but the risk and downside consequences could be very high and unacceptable.

An adversary calling a country’s bluff on a contrived red line will be emboldened and feel unconstrained by the lack of seriousness implied by a bluff.

Emboldening the adversary

Even if a red line policy is completely rational, it is still very possible that an adversary may take the red line as a challenge and even an embarrassment or insult to be overcome and be emboldened to maybe even go further than if the red line had not been declared.

Failure of diplomacy

In truth, the mere admission that a red line may be needed indicates that the country has failed to conduct the kind of diplomatic heavy lifting that would have avoided the adverse situation in the first place.

Even if the red line is obeyed, the underlying adversarial relationship remains, as do the prospects for future, fresh, new conflicts.

Any failures of diplomatic efforts may or may not be due to or solely due to the adversary. The adversary may indeed be in the wrong, but the nature of true diplomacy is not assigning blame, but finding a successful path forward. The fixing of blame should never be viewed as an excuse or reason for abandoning diplomacy or asserting that the onus is solely or primarily on the adversary.

Normal diplomacy

Normal diplomacy is best conducted out of sight, behind closed doors, in private, with the relevant parties. It may be direct between the impacted parties, or may be indirect with third-party intermediaries and backchannels when the relationships between the parties are too strained.

Any public statements should focus on exhorting the positive qualities of relations, minimizing differences, and explaining not the details of any private discussions, but simply pointing out that relevant discussions are occurring as they should, in private.

Again, any public red line policy is more an admission that normal diplomacy has failed, which may or may not be due to or solely due to the adversary.

Delaying unpleasant work

Resorting to the drawing of a red line simply delays any hard work that may be needed to resolve the conflict and may make it even harder down the road. Absent the red line, the unpleasant work needed to resolve the confrontation would progress, even if that means extreme conflict — at least a solution will more quickly be at hand, or at least it will become clear that the aggrieved country is not going to get the satisfaction they desire and they should resolve to live with life as it is.

In short, a red line may simply be being used as an excuse to delay action, and probably an excuse for not taking the immediate but difficult steps that are really needed to prevent the situation from becoming critical in the first place.

Defensive use of red lines

It may be tempting to use a red line in a defensive manner to simply delay direct action, by drawing the red line far enough down the road so that it is unlikely to be reached or at least not reached until a significant period of time has elapsed — or maybe the underlying problem will resolve itself or be resolved by other parties.

This does not appear to be a wise use of a red line, but foreign policy is not always as clear cut and tidy as one might desire.

But if there is some significant degree of likelihood of resolution, either by the adversary or third parties, the use of a red line to encourage or incentivize that likely resolution is not necessarily such a bad thing. It all depends. Again, the important thing is to do a careful analysis of the situation before drawing a red line in public.

Pro forma red lines

A red line might be drawn on a pro forma basis, simply to say that it is there, possibly for domestic political cover or to avoid looking weak. There may not be any expectation that the red line might realistically be violated, but again, its mere existence at least seems like a wise move, although appearances can be very deceiving.

That said, a pro forma red line has a high probability of being either useless or a move that will later be regretted since an unexpected violation would then incur a forced response that may not have been adequately anticipated.


Flexibility is a truly fantastic tool, allowing freedom to adapt to situations as they emerge and evolve, but red lines virtually eliminate flexibility in exchange for a fixed response, no longer permitting an evolution of the response or the conditions for the response.

Granted, there is some benefit to commitment, but exchanging flexibility for the certainty of a commitment is a decision that should not be taken lightly.

Careful consideration

The use of red lines needs to be carefully considered, not knee-jerk or off the cuff or answering gotcha questions from the media at a press conference. Consideration should include:

  • Careful evaluation of all alternatives short of the use of red lines.
  • Gaming all the alternative scenarios leading up to the red line and all the downstream effects of the consequences of the response to crossing the red line.
  • Planning a cooling off period, to assure that the red line is not a knee-jerk, emotional response.
  • Internal inter-agency discussions about all of the ramifications of such a red line.
  • Private inter-governmental discussions with allies concerning both the adversarial situation and the proposed red line.
  • Informal, tentative reaching out to the adversary using backchannels to warn of the impending red line, to try to head it off.

Clear public statement

The public statement of a red line should be a formal statement, not a casual, informal comment to the media. The process should include:

  • Clear public release of a formal statement on the situation, the actual red line with great clarity, how the red line can be avoided, and a clear warning of the general nature and severity of the consequences. The specifics of the consequences generally can’t be spelled out, but the general level of their severity can and should be summarized clearly, crisply, and unequivocally.
  • Privately review the statement with at least key allies.
  • Privately run the statement past a few trusted members of the press to assure that they can comprehend it and that it does not confuse them or cause them to misrepresent it.
  • Refrain from spinning the statement to the press.
  • Push back very stiffly and harshly on any attempts by the press to spin the statement.

Technical difficulty of confirming violations

Even if a red line violation is obvious in the abstract, there may be significant technical obstacles to achieving a solid confirmation of a violation. Potential issues include:

  • Ambiguous signals — more than one activity might cause the same measurable conditions, not all of which may be actual red line violations.
  • Accidental violation rather than an intent to cross the red line.
  • Third party violating the red line to make it look as if the adversary had crossed the red line.
  • Technical issues with measuring the violation, such as lack of direct access to the geographic location where the violation occurred.

In any case, the formal statement of the red line policy needs to clearly lay out the conditions and criteria for detecting violations.

Soft red lines?

It may be tempting to declare a soft red line, one which has some flexibility in the criteria for judging violations, but the risk is high that an adversary will see the softness as a weakness to exploit and that the red line lacks credibility.

A soft red line may be appropriate in some scenarios, but the softness needs to be very clearly bounded so that there is no weakness implied.

Any softness should be framed very carefully so as to not introduce a level of ambiguity that turns the whole red line into a loophole that can be driven through as if there were no red line at all.

Need for careful statement of consequences

The consequences for exceeding a given red line are unlikely to be spelled out very specifically in advance, in part because they should depend on exactly how the red line was breached and the exact context at that moment. And despite the certainty of the red line, there remains the desire and benefit of retaining at least some degree of flexibility in the response. Nonetheless, there does need to be some clear statement, in advance, about the consequences.

It is okay for consequences to be somewhat ambiguous, provided that the ambiguity is reasonably explicit.

It may be better to specify a range of consequences.

At a minimum it should be made clear whether or not the most extreme possible consequences are the only possible consequences.

It should be made crystal clear how the red line will be used to shape the consequences.

Nonetheless, it is beneficial to avoid an overly-precise, overly-narrow response that could have the negative side effects of limiting flexibility and undermining credibility.

The bottom line is that the statement of consequences needs to be very balanced to fit the nature of the red line, neither excessively specific not excessively vague — just specific enough and just vague enough.

Perceived red lines

Tough talk and aggressive and vague language will likely lead to a situation where observers perceive that a red line has been drawn even though no official has explicitly drawn a red line. To be clear, no explicit red line has been drawn, but observers are intuiting and presuming that a red line is indeed in place.

The upside of a perceived red line is that it has a lot of the benefits of an explicit red line, but without the need for a full commitment.

The downside of a perceived red line is that if and when the perceived red line is actually crossed, the country will suffer from just as bad a loss of credibility if no significant response occurs as if an explicit red line had been in place.

There is no actual red line in place for a perceived red line. The perception is a mistake on the part of the observer, although the official gets part of the blame for using vague language. No adversary can be blamed for acting as if the perceived red line did not exist.

In summary, a perceived red line leaves ambiguous whether a red line was intended or whether the observer is making a mistake by assuming a red line was implied. This may be useful in some situations, but is a very dangerous ploy and not really advised as a general proposition.

Officials will need to keep a wary eye on the press to see if they start talking as if a red line was drawn when officials had no such intent.

Apparent and implicit red lines

In addition to observers reading between the lines and intuiting that a red line is intended, officials may use language that seems to actually imply that a red line is intended, even if the language does not make the red line explicit.

Direct language such as “I/we (absolutely) won’t” accept something, clearly implies a red line.

Similarly, direct language such as “I/we (absolutely) demand” something, clearly implies a red line.

The distinction between a perceived red line and an apparent or implicit red line is that the former is not an actual red line while the latter is an actual red line. An adversary can be excused for ignoring perceived red lines but is well advised to pay great attention to apparent and implicit red lines.

Hinted red lines

Sandwiched between perceived and implied red lines are hinted red lines, where the official is intentionally being vague to get much of the benefit of a declared red line without the downside of making and following through on a committed consequence.

It may even be a strongly hinted red line, as toughly-worded as can be but still falling short of the explicit language of an apparent or implicit red line.

Hinted and strongly hinted red lines are like walking on thin ice — they may work and be quite effective, or could backfire badly. An adversary could call your bluff and proceed to violate the hinted red line and then keep on going without any severe consequences.

In practice, an official using hinted and strongly hinted red lines is most probably being lazy and taking a short cut. The recommended course would be to pursue traditional and normal foreign policy alternatives to their fullest, and only then proceed to a full evaluation of a full red line, and stay away from the lazy short cut that may feel good but take an unnecessary risk.

Perception vs. reality

Reality is more important than perception, but all too often perception can overwhelm reality.

The difficulty is that perception is frequently very difficult if not impossible to manage and impossible to control in any absolute sense.

Still, it is essential to pay more than simply lip service to perception.

When perception does overtake reality, it is commonly due to missteps or unforced errors. Sure, perception is also commonly influenced by intentional actors other than the principal, but sometimes that is beneficial rather than strictly negative.

The bottom line is that perception is a valuable component of the implementation of policy.

Perception of a red line has several components:

  1. The value or need for the red line at all.
  2. The credibility of the threshold for the red line itself.
  3. The credibility that severe consequences will indeed be carried out.
  4. The credibility that the severe consequences will successfully resolve the situation.

Red lines as mere rhetorical or literary devices

Red lines should only be drawn as a matter of formal foreign policy, but unfortunately they may be used a bit too casually as mere rhetorical or literary devices, simply to leave a strong impression on people, for emphasis, and intended more for the moment only rather than as a longer-term and durable commitment.

Needless to say, red lines should not be used casually as rhetorical or literary devices.

Red lines without consequences?

It sounds like a true oxymoron, but a red line without definite consequences is not so uncommon, and is not exactly the most advisable approach to resolving a confrontation.

A red line should either be coupled with definite consequences, or should not be deployed as a red line at all.

Without definite consequences, a red line is certainly a mere rhetorical, literary device, and likely to be treated as such by any adversary and allies alike.

Technically, a red line withut definite consequences is simply a strong warning, but by delivering it in the form of a red line, a country is undermining its own credibility by behaving in a somewhat irrational manner.

Domestic political dimensions

Although red lines should be used strictly as a means of pursuing foreign policy, they will usually have domestic political dimensions as well, such as:

  • To avoid looking weak to domestic political opponents and supporters alike.
  • To look tougher as a political player.
  • To avoid threats to personal and party ego.
  • To appeal to or attract fringe group supporters.
  • To appeal to large financial donors.
  • To distract from domestic issues.
  • To distract from personal issues and embarrassments.
  • Forced by competing interests within the party.
  • Forced by agreed upon part platform agenda.

Intra-party political dimensions

Beyond simply domestic politics in general, an official may be pursuing a red line policy simply for intra-party dimensions, such as:

  • Fighting off competition.
  • Scoring points to maintain standing within the party.
  • Pursuing the party platform agenda.
  • Keeping big financial donors happy.

Red line policies should not be used to address domestic intra-party political concerns, but that is part of the nature of politics.

Such efforts interfere with international relations and end up sending confusing signals to allies and adversaries alike.

Credibility of the red line is at stake as well, since there is also the risk that allies and adversaries will not take the red line policy seriously if they feel that a change of parties in a future election might cause the commitment to the red line policy to be weakened or even reversed.

Private vs. public red lines

Most of the discussion and concerns here relate to the special problems with red lines that are drawn publicly to great fanfare.

One of the biggest issues at stake with a very public red line is a matter of face and ego being at stake.

It is one thing to privately communicate a stern warning to an adversary. The adversary might respond in a huffy manner, but there would be no public threat to the egos of the parties involved.

It is an entirely different matter to publicly condemn and threaten an adversary and commit to a course of action. Face is at stake. Ego is at stake. Emotions will run high. Risk of making mistakes is high.


Separate from any official declaration of a red line policy, a wide variety of surrogates could declare an implied red line without the U.S. itself having to make a commitment. Surrogates could include:

  • Allies.
  • Members of Congress — speaking for themselves, but implying that the whole of the U.S. might back a particular red line policy.
  • Former government officials.
  • Esteemed academics.
  • Esteemed pundits and commentators.
  • Activists — maybe only saying what U.S. policy should be, but making clear what they think is the right thing to do.
  • Esteemed think tank fellows and analysts.

And some combination of surrogates could reinforce each other to carry more weight.

Granted, a surrogate red line carries no committed force, but it can still convey a strong message and leave the adversary wondering whether there may indeed be an implied red line policy in place.


Toughness is a classic double-edged sword, sometimes facilitating a successful defense of a country, but too often getting in the way and precluding more pragmatic and effective solutions to policy issues.

Emotion-charged toughness is more commonly valued in domestic politics, seeking to dominate weaker opponents. Internationally it is less effective, where allies and adversaries alike are more interested in the pragmatic aspects of level of dispassionate commitment rather than bluster and knee-jerk reactions. Besides, officials in other countries have their own domestic political situations to cope with, so that toughness by external parties may be of little concern.

Red lines can be tinged with that domestic, emotionally-charged toughness, but those are the kind of red lines that either crumble when tested, are eventually forgotten or withdrawn, or can have disastrous consequences if actually carried out.

In summary, raw toughness is a poor substitute for diligent discipline and commitment.

That said, domestic politics can demand that an official talk tough in public even if acting more moderate in private. Balancing the two is crucial.

Who is the audience?

There are many audiences for any public statement, including the drawing of red lines, such as:

  • Domestic citizens.
  • Allies.
  • Citizens of allied countries.
  • The adversary.
  • The citizenry of the adversary.
  • Members and leaders of the official’s political party.
  • The media.
  • Experts.
  • Pundits.
  • Business leaders.
  • Voters — the subset of citizens who are politically active.

Each audience will have its own set of issues that it most cares about.

A message to one audience may have an opposite or neutral effect on some other audience.

Sometimes a message that seems off, flat, or too aggressive may really simply be intended for some other audience than the listener presumes.

In the case of a red line, there may be the need for a number of public messages, each tuned for the intended audience.

What is the purpose of the red line?

More than just the literally stated objective of the red line, there is usually some combination of ulterior motives for engaging in the drawing of a red line, such as:

  • To calm anxiety among the domestic citizenry.
  • To incite a drum beat among the domestic citizenry.
  • To calm allies.
  • To shake things up with allies who are wobbly.
  • To deal with intra-party political issues, to quell unrest, or to keep or gain control of the party.
  • Election posturing.
  • To satisfy media who may be stirring the pot and making the government look weak.

The public messaging of the red line policy may or may not make this purpose clear, but there should at least be clarity in the internal deliberations to clearly identify and focus on the intended purpose, as well as identifying and mitigating any collateral impact on other groups and other areas beyond the intended purpose.

Pressure to draw a red line

There may be intense pressure to draw a red line, pressure to act, but that’s usually a bad reason to actually draw a red line. A careful evaluation of the alternatives should always precede the drawing of a red line.

Pressure to act

Sometimes the motivation for drawing a red line is simply a reluctance to take a direct action that actually is warranted, and that the drawing of the red line is simply a delaying tactic.

This is a dangerous situation, since the adversary is likely to ferret out this motivation and see it as a weakness to be exploited.

Slippery slope

Red lines should not be viewed in isolation. Although the consequences of a violation may seem completely warranted, a careful assessment should be made to ascertain where exactly the situation will end up after the consequences play out. It may in fact be on a slippery slope where the downstream effects from the consequences end up snowballing in a manner that is far worse than the original scenario.

For example, a regime in relative stability could segue into a chaotic environment with unimagined consequences, so that a short-term aim might be achieved but at a cost of longer-term stability.

Role of personality, emotion, and ego

Beyond any realistic rationale for a red line, it may simply be personal, a matter of emotion and the official’s ego. Sure, it shouldn’t be that way, but ego is a part of the equation of human nature — government officials are not machines.

When analyzing a red line scenario, it is helpful to consider the aspects of the rationale for a red line that are based on the human nature of all parties involved.

Even if the official drawing the red line is completely rational, there is also the potential for a personal, emotional, ego-based reaction on the part of the adversary.

Even if the relevant officials of the adversary are purely rational, the citizenry, legislatures, advisers, and government staff of the adversary might have a more visceral reaction which could indeed overwhelm any rational reaction of the nominal officials who should be responding to the drawing of the red line.

In short, a nominally completely rational red line could easily blow up in some disastrous manner once human nature enters the equation. The analysis and assessment in the planning stage for a red line needs to take personality, emotion, and ego into account.

Human nature

Although a red line policy should be a strictly intellectual and political matter, where reason and rational behavior rule, basic human nature plays a strong role. In addition to personality, status, and ego,officials must cope with all manner of human nature factors, such as:

  • How the human mind works when under pressure.
  • The limits of human tolerance.
  • Everyone has a breaking point.
  • What should people do when they can’t take it anymore?
  • The human desire to react (fight.)
  • The human desire to delay action (flight.)

The analysis and assessment in the planning stage for a red line needs to fully take human nature into account.

Red lines as an act of weakness

Nominally the drawing of a red line would seem to be an act of strength and courage, but the opposite is possible as well — it could be an act of weakness, an admission of failure to successfully find and pursue more practical solutions to the controversy at hand. It could indicate a lack of discipline, an inability to focus on practical matters, or a weak will and inability to cope with peer pressure.


A red line can certainly be drawn as an act of brinkmanship, more as a provocative dare than a true deterrent, but this has high risk. Great care and focus are needed. This approach can only be used very selectively.

The flip side is that a seemingly prudent red line can inadvertently lead to a brink condition where one is forced to either back down from the red line consequences or follow through with further consequences that may not have been adequately anticipated.

Confident implementation is essential

Smooth, steady, and confident implementation of a red line policy is essential and critical. Any tentativeness or hesitancy in either putting the threshold monitoring into place or execution of the consequences on a violation of the red line will quickly undermine and eliminate the effectiveness of the red line. Credibility is at stake. There is no room for creating or allowing doubt to come into the picture.


Rather than leap directly to the severe regimen of a red line, a range of alternatives can be pursued:

  1. Normal diplomacy that may have been skipped or short-changed.
  2. Serious warning, but without explicit red line commitment to action.
  3. Strategic ambiguity — provides a lot of the same qualities but without the extreme, committed inflexibility of a red line.
  4. Back channel talks.
  5. Private talks.
  6. Prompt action — if the situation is so bad, then swift, decisive, unequivocal action can resolve the situation without dragging the process out.
  7. Partial action — far less than the full severe consequences of a red line, but enough to persuade the adversary that the country means business.

Serious warning vs. red line

A traditional strong warning about undesirable behavior may sometimes be as effective as a formal red line.

A strong warning verges on being a red line once explicit language about the prospect for consequences is used. A warning may simply indicate that there may or are likely to be consequences, while a red line will clearly indicate that there will be consequences.

Even without any explicit reference to the prospect of consequences, a serious warning may be perceived as an implicit red line.

Nonetheless, warnings and serious warnings are still very useful tools to deter and respond to unacceptable behavior on the international front.

Degrees of warning

The toolkit for foreign policy should have a very wide range of severity of warnings, from very mild to extremely severe. A red line is towards the severe end of the spectrum, and with the explicit threat of consequences included.

The essence of a warning is to put the adversary on notice that they are on the radar and that further misbehavior is only going to heighten the scrutiny on them.

A warning is nominally a yellow, caution flag, but as with true red lines, more severe warnings are effectively red flags as well.

Levels of warning might include:

  • Concern.
  • Significant concern.
  • Grave concern.
  • Unacceptable.
  • Absolutely unacceptable.
  • Forbidden.

The level can also be indicated by:

  • Rank or level of official issuing the warning..
  • Frequency of repetition.
  • Length and detail of warning.

In any case, skipping directly to a red line is not likely to be the most useful path, especially since it will inherently reduce flexibility.

Strategic ambiguity

Strategic ambiguity differs from a red line by leaving either or both the precise demarcation of the threshold and the resulting response ambiguous, replacing the constraining nature of a clear threshold and response with a strong warning that continued progress in the specified direction will draw increasing scrutiny and runs an ever-greater risk of an escalating response.

This raises the ante in the confrontation but without overly-constraining flexibility.

The only problematic issues with strategic ambiguity are:

  1. Requires as much analysis, planning, and follow-through as a red line.
  2. Requires as much senior-level attention as a red line.
  3. Raises the anxiety level almost as much as a red line.
  4. Leaves a lot of uncertainty about how events will unfold.

The advantages are:

  1. Greatly increased flexibility.
  2. Less of a risk or threat of immediate severe consequences.
  3. More opportunity for exploring alternative approaches to resolving the confrontation.
  4. Provides more opportunity for a cooling off period.
  5. Uncertainty prevents adversaries from firming up a solid defense.
  6. Lack of a direct threat denies adversaries a specific threat to respond to.
  7. Less risk with putting the policy into place.
  8. Permits a staged response rather than a sit and wait period followed by only a severe response.
  9. Can always transition to a true red line policy down the road anyway.


Media doesn’t have some special right to declare red lines on behalf of officials, to tease out implied red lines, or goad officials into off-the-cuff red line comments.

Media must restrict itself to solely and accurately reporting literal official comments on red lines and refrain from adding its own spin on red lines.

Media should limit itself to reporting the facts of actual, factual, official red lines and refrain from reading between the lines and attempting to infer anything about them.

That said, officials must exercise great diligence and restraint to compensate for the lack of the same on the part of the media.

That said, the media also needs to be on the alert and feel free to call out officials when they get careless and sloppy or excessive with red line and near-read line scenarios.

Psychological warfare

Beyond any practical ramifications of a particular red line policy, a red line can be used as a form of psychological warfare, not just to cow them into submission on a particular issue, but to undermine their will and determination even on issues beyond the specifics of the particular red line.

Nuclear weapons

Nuclear weapons are a special case in many ways. Normal rules for red lines simply don’t fit well at all, such as the doctrines of mutually-assured destruction and no first use.

That said, red lines can indeed be used effectively for deterring acquisition of nuclear weapons and nuclear weapons technology. But, that also depends heavily on carefully planned thresholds and disciplined execution of consequences on violations.

That said, the difficulty of successfully using red lines for these scenarios argues strongly in favor of shorter-term and less severe alternatives, as well as broader and longer-term options that leave less to chance and short-term interpretation..

There may indeed be non-public but explicit red lines on a variety of aspects of the acquisition and use of nuclear weapons that are beyond the scope of public discussion and media coverage.

Existential threats

It is unclear whether red lines have an effective role in dealing with existential threats. As with nuclear weapons, existential threats in general are in a completely different league from garden-variety foreign policy issues.

Granted, a policy of mutually-assured destruction is essentially an extreme form of red line, but it is so far beyond a normal red line that the red line concept doesn’t seem relevant in any normal sense.

Certainly it would be inappropriate to attempt to treat non-existential issues as being on the same level as existential threats.

As a general proposition, it is questionable whether potential existential threats should be discussed in public at all. Granted, nuclear mutually-assured destruction has been discussed in great detail in public, but thankfully that’s about as far as public discussion of existential threats has gone.

Review of existing U.S. foreign policies

Given our history of pursuing red lines in a haphazard manner, it would make a lot of sense to carefully review all U.S. foreign policies to clarify whether or to what extent they contain either explicit red lines or implied red lines, or whether they have so much ambiguity or vagueness as to make it unclear whether a red line might or might not be involved.

In many cases strategic ambiguity may be sufficient. If not, then the red line nature of a particular policy should be much more carefully analyzed and clarified.

Such review should occur periodically as circumstances, technologies, political considerations, and overall foreign and international relations evolve over extended periods of time. What deserves or constitutes a red line today may not tomorrow, and what does not deserve or constitute a red line today may tomorrow. And if not tomorrow, then maybe the day after tomorrow.

That said, too-frequent review and adjustment can be disruptive and undermine credibility as well. Balance is always the right answer.

Confidential red lines

For some extreme and sensitive scenarios there may indeed be a wide variety of undisclosed red lines. They may offend or threaten even allies, or may telegraph information to adversaries that should better be kept confidential. A country may have covert intelligence about an adversary and not wish to let that adversary know that the intelligence is possessed, especially its sources.

The advantage of a confidential red line is that it has none of the public affairs downsides. Executive action can create, remove, or modify a confidential red line without risk of public embarrassment or at any cost of political capital.

All of that said, confidential red lines have many of the same downsides as public red lines, especially the loss of flexibility.

In truth, a confidential red line is not of any greater utility than strategic ambiguity, which permits a more staged and nuanced response, which can become critical for scenarios that are evolving in a dynamic and unpredictable manner. An advantage may be that status as a red line can give a policy greater visibility, attention, priority, and resources.


Keep It Simple Stupid — careful attention to detail is needed in any policy directives, but too much complexity can be very problematic. Complexity can lead to confusion. Non-strategic ambiguity can mislead adversaries (and allies) into believing that particular undesirable actions might be acceptable through some oversight or explicit or unintentional loophole.

How concrete is a red line?

Exactly how concrete is a red line?

Can it be shifted? Does any shift completely undermine it? Does its red nature mean that once set it cannot be changed without a complete loss of credibility?

Can it be fully removed once put in place? Again, the credibility question comes up.

Does it allow any flexibility? Is any wiggle room permitted, or would that again raise the credibility question?

Living under red lines

Even if a red line is actually fully effective and deemed very necessary, that effectiveness may come at a great social cost. It may put an ominous damper on the vitality and vibrancy of society. People may begin to live in fear that something bad is about to happen at any and all moments.

And as certain as a red line sounds, there are multiple dimensions of uncertainty that collectively add a level of uncertainty to the lives of individuals and businesses, in an already uncertain world.

Multiple dimensions of uncertainty

Even if a red line policy is very carefully considered, very carefully stated in public, and very competently implemented, a host of uncertainties will still exist, such as:

  • Will the red line have the desired deterrent effect?
  • Will the red line limit only especially bad behavior, but still allow all manner of bad behavior short of the red line?
  • How certain is the monitoring for violations?
  • How certain is any grace period for inadvertent or accidental violations?
  • How effective will consequences be on a violation?
  • How swift will consequences be on a violation?
  • How sure and confident will consequences be on a violation?
  • How will the adversary actually perceive consequences on a violation?
  • How will the adversary respond to the consequences on a violation?
  • Might the adversary accept the consequences and proceed unbowed?
  • Might the adversary respond to the consequences on a violation with some extreme response that is far worse than the actual act of the violation?
  • What unknowable unknowns are lurking out there?
  • What do officials know privately that they are not discussing publicly?

Ex post facto red lines as casus belli

A red line is generally drawn in advance, but since red lines are primarily rhetorical devices, they can also simply be used in an ex post facto manner, after the fact, as a casus belli, as a cause or reason or justification for severe action, even military action.

In other words, consequential action may be justified by declaring that an action, condition, or behavior of an adversary constitutes a red line that has been crossed, even though no red line was actually drawn in advance.

In truth, it may simply be due to an oversight or lack of attention that no red line was explicitly drawn in advance. Or maybe a private or confidential red line was indeed drawn. Or, maybe it was politically inadvisable or too difficult to draw the red line at a more appropriate time.

This may not be the most appropriate use of a red line, but works as a rhetorical device.

Executive prerogative

Regardless of the relative merits of a red line policy, ultimately it remains the executive prerogative of the president as to the final decision about its use as a tool of foreign policy and national security.

Even if serious analysts agree that a particular red line is a bad idea, the president still has a role based on a broader perspective and ultimate responsibility for foreign policy and national security. That broader perspective may provide insights unavailable to mere analysts.

Legal ramifications?

It is unclear whether red lines have any significance in international law.

Are they fighting words?

Do they constitute an actual threat that an adversary could legally respond to?

Still, red lines are a valid tool

For all of the concerns and potential downsides, red lines still deserve a place in the toolkit of foreign policy. There may well be scenarios which are too important to leave to chance, uncertainty, ambiguity, or misunderstanding to depend on any option short of an explicitly declared red line.

But, it does require a lot of careful thought, consideration, analysis, assessment, and decision-making.

There may be non-obvious consequences of a red line, beyond the declared intentions.

An intentional cooling off period should be required before any proposed red line is actually put into place. All reasonable alternatives should be evaluated during that period. Even after all plausible options have been evaluated and rejected, an additional cooling off period, a quiet period, is appropriate to truly confirm that the situation is unlikely to resolve itself with a dissipation of strong emotions.

In any case, a red line can never be used as a knee-jerk reaction. It is not easy or even possible to take it back without severe consequences.

An ally or multilateral organization or even an ally of the adversary might have some luck resolving the situation during the cooling off period.

Is a red line ever the best choice?

Even if there are scenarios where no other alternative appears to be viable, the suitability of a red line is still highly suspect. In truth, it really does mean that there has been a fundamental failure of foreign policy that more modest and more appropriate options have not been used as effectively as they could have been. That said, few government policies are ever implemented as effectively as possible, so failures of foreign policy are a reality that must be dealt with.

A red line policy is the ultimate fallback, even if not the ultimate best policy.

Red lines drawn by adversaries

This paper focuses on the drawing of red lines and their utility, but does not cover the drawing of red lines by adversaries. That’s an interesting topic, but beyond the scope of this paper. Nonetheless, a few comments are warranted.

If an adversary does draw a red line and threaten the U.S. with severe consequences, some questions arise, such as:

  • How should the U.S. defend against the use of red lines by adversaries?
  • Can an adversary’s red lines be challenged? If so, how?
  • What is the legal status of threats in the form of red lines drawn by adversaries?


Red lines will likely continue to be used and misused in a haphazard manner for the indefinite future, but a few points seem clear:

  1. Generally red lines should not be used.
  2. Preserving flexibility usually has greater value than dubious deterrent value.
  3. Only in extreme situations are red lines appropriate.
  4. They should be deployed only after careful analysis, deliberation, and a robust decision-making process, and with careful attention to how presented in public.
  5. A clear statement of the red line is essential.
  6. A clear statement about consequences is essential.
  7. A red line must have definite consequences.
  8. Red lines should never be used as off-the-cuff press comments.
  9. They should not be used as a negotiating ploy.
  10. Bluffing is unlikely to be a reliable strategy.
  11. Strategic ambiguity is a superior tool for warning of areas of great concern.
  12. Various levels of warning can be helpful.
  13. Credibility and commitment are crucial.
  14. Red lines should be kept in the foreign policy tool kit, again only for extreme situations.
  15. Media must refrain from adding its own spin to official statements about red lines or attempting to infer implied red lines.
  16. Periodically review existing U.S. foreign policies as to whether they may constitute implicit red lines which should either be explicit red lines or clarified so as to explicitly not be red lines, implicit or otherwise.

The real bottom line is that instead of getting better at using red lines, countries need to get better at managing international relations so that fewer red lines are needed. Too often, problems are permitted to fester and relations are permitted to decay, so that issues become crises when they could have been dealt with much more adequately with earlier and more disciplined attention.




Freelance Consultant

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Jack Krupansky

Jack Krupansky

Freelance Consultant

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