9. September 2026
Why is the Russia-Ukraine war continuing even though both war parties say they want peace? What would bring about a robust ceasefire? And what can other states do to help? Answers to these questions can be found in a key approach in peace and conflict studies known as ripeness theory.
Developed mainly by I. William Zartman, ripeness theory seeks to explain the conditions under which war parties seriously consider substantial peace negotiations. According to the theory, this happens when three conditions simultaneously apply: both parties believe that the conflict has reached a stalemate, that this stalemate hurts their vital interests, and that there is a preferable alternative to continued fighting.
The theory overlaps with other established concepts in the research literature on peace and negotiations. The best alternative to a negotiated agreement, often abridged as BATNA, represents the most advantageous course of action a party can take if negotiations fail and an agreement cannot be reached. If both war parties believe the war is going nowhere while consuming crucial resources, their BATNAs are unattractive, increasing the chance that there might be a zone of possible agreement (ZOPA) between them.
But is ripeness theory “just a theory”? Why should citizens and policymakers care about it?
Why Theory Matters
Theories are tools for understanding and organizing reality. They simplify complex social processes by identifying relationships between causes and outcomes. A sound theory should therefore be conceptually clear, internally consistent, and supported by empirical evidence.
While people can make sense out of situations without directly using theories, they cannot escape theoretical assumptions; they merely rely on less explicit ones. What appears to be common sense or intuition is often a heuristic or ‘rule of thumb’ based on an underlying yet unexamined theory of how the world works.
For peace and conflict research, this matters because analysts and policymakers routinely make causal judgements. For example, the Trump administration recently said that it would inflict an “economic D-Day” on Iran and that this would force Teheran to change its policy in the strait of Hormuz. Such judgments require assumptions about cause and effect. False assumptions beget false judgements, bringing forth bad policies. Theory-based analysis helps to make such assumptions explicit and examine them critically.
Theories are therefore particularly relevant for forecasting and scenario analysis. They identify mechanisms that help analysts consider how changes in one part of a conflict may affect other parts.
What is Ripeness Theory Good For?
Ripeness is not the only path by which wars can be settled via negotiations. Recent research shows that many cases involve parties where one party is clearly stronger than the other. Thus, while Zartmann’s ripeness probably represents a plausible or sufficient path to ending conflicts through negotiations, it is not a certain or necessary path. Indeed, there seem to be others.
Marieke Kleiboer and Eamonn O’kane have argued that the core concepts of ripeness theory are difficult to measure reliably, particularly when meaningful negotiations have not yet taken place and information about ripeness would be most valuable. Indeed, war parties usually know more about their own intentions and capabilities than others, while their biases and interpretations are often impossible to assess from the outside.
This problem is not unique to ripeness theory. Many concepts in social science – for example, political will, legitimacy, resolve, or threat perception – are difficult to observe directly. Ripeness theory is ill-suited to predict exactly when and how particular conflict parties will actually negotiate. What the theory is still useful for is systematically assessing other aspects of conflicts and prospects for peace.
Why Is Everyone Selling Peace, but Nobody Is Buying?
Ripeness theory offers an answer to the question of the ‘marketability’ of peace (an issue once raised most pointedly by the thrash metal band Megadeth).
Warring parties often claim that they are ready to negotiate for peace. Sometimes, however, they make this claim despite not being actually willing to drop any of their demands. Following the BATNA logic, they believe they have a better alternative to a negotiated agreement. However, they continue to claim that they are ready to negotiate for peace because doing so can be strategically advantageous. For example, such signals can increase support for their demands by third parties or weaken support for the enemy.
Ripeness theory helps in distinguishing sincere signals for negotiations from insincere ones. If negotiation-readiness is signaled while a warring party is under observable strain and has something to gain from peace, BATNA logic dictates that negotiated agreements involving compromises are more attractive to them. Consequently, signals from such warring parties should be taken more seriously.
Arguably, this currently applies more to Ukraine than to Russia, as Ukraine is under more pressure. Compared to continuing to suffer under Russia’s attacks, Ukraine would benefit from an unconditional ceasefire – which is exactly what Ukraine has been long been calling for, giving credibility to its signals. The Russian regime, on the other hand, can hope that by continuously pressuring Ukraine, Western support or Ukrainian resolve might eventually fade, allowing Russia to realize its maximalist war aims. This, in turn, makes it more attractive for the Russian regime to continue to fight while claiming to seek peace. Ripeness theory therefore suggests that the apparent readiness of the Russian regime to seek peace should not be taken at face value.
Furthermore, ripeness theory helps to explain why both war parties have so far been unable to find common ground for a ceasefire. As argued here and here, while Ukraine suffers immensely under the war, giving in to Russia’s demands – permanently ceding large chunks of territory, risking domestic instability, and rendering itself defenseless against a new Russian attack – would probably involve significantly higher political costs and risks for Ukraine than to keep fighting and hoping that the situation will improve over time. The Russian regime, on the other hand, has been under less pressure, giving it little incentive to drop its maximalist demands. In other words, because there is no stalemate that sufficiently hurts the Russian side, there is no space of possible agreement between both parties that would enable serious negotiations.
What Can Be Done?
Ripeness theory gives cues to third parties on how they can bring about a ripe moment for serious peace negotiations. Third parties can offer side payments to both parties to make a negotiated “way out” more attractive. Furthermore, they can help to reduce mutual misunderstandings and point to “mutually enticing opportunities”.
In an asymmetric conflict, mediators can also facilitate a mutually hurting stalemate by supporting the weaker party. This requires careful calibration, as insufficient support would not bring about a stalemate while too much support could diminish the supported side’s willingness to make concessions to the unsupported side. This, in turn, could lead to a situation where attempts at creating a hurtful stalemate inadvertently sabotage the “way out”.
Hence, ripeness theory suggests the following strategy to reach a robust peace in Eastern Europe: support the weaker party, Ukraine while putting pressure on the more powerful party, Russia. Doing so would help creating a situation in which the Russian regime increasingly loses confidence in achieving a maximalist victory by continued force and begins to look for more diplomatic alternatives. Simultaneously, third parties should work towards a concession package that respects the vital interests of Ukraine and its European allies while creating more incentives for Russia to agree. This could, for example, include post-conflict sanction relief for Moscow.
Looking back at the Trump administration’s erratic policy toward Ukraine and Russia since early 2025, ripeness theory helps to understand why Trump was unable to end the war quickly: The Trump administration pressured the weaker side, Ukraine, into making politically unacceptable concessions while signaling to Russia that this pressure might increase even further in the future, disincentivizing Russia from considering winding down its military pressure. Had the Trump administration considered ripeness theory, we might live in a more peaceful world today.
