As the Ukraine war approaches its four-and-a-half year milestone, the sustainability of the coalition of support for Kyiv has once again become a key question on the minds of Europeans.YouGov data from February 2026 shows considerable variation among Europeans in support for maintaining the war effort. Support for a negotiated peace has overtaken that for holding out for Russian withdrawal in France, Germany and Spain. Ukraine has also become a key political issue in Italy ahead of elections in 2027. Larger parties, such as Prime Minister Giorgia Meloni’s Brothers of Italy and the centre-left Democratic party, have maintained their support for Ukraine. But smaller parties both on the left and right, including the Five Star Movement and Lega Nord, are showing little appetite for continuing military aid.How can we assess how much strain the coalition of western democracies supporting Ukraine is really under? After all, we have seemingly been here several times before. We believe the key is understanding the sources of “war fatigue” and the willingness and ability of parties to capitalise on it. War fatigueOne the many unfair aspects of the war is the contrast between the autocratic Russian regime, which is able to mobilise societal resources rapidly and impose its will on its own citizens, and the coalition supporting Ukraine.Maintaining this disparate coalition requires constant maintenance of the relationship with other coalition partners and with domestic electorates to ensure continued support is forthcoming and to prevent the defection of partners. However, citizen support is not something that can be taken for granted. As conflicts become drawn out, this support can increasingly come to waver.War fatigue isn’t just a question of the longevity of a conflict. It is also a question of the costs imposed upon citizens and their cumulative impact over time. Fighting wars implies trade-offs between public and military spending, which citizens may not be willing to tolerate over the long term.Vladimir Putin’s weaponisation of the energy supply to Europe, by periodically tightening the flow of natural gas, reflects a keen awareness on the Russian president’s part of this dynamic. His bet seems to be that Russian resolve can outlast that of the Europeans.War fatigue also depends on the perception of success. Citizens will be far more willing to support the cause if they think there is a high likelihood of victory. They will be less willing to back initiatives where there will be no return.The first wobbles in the coalition, in late 2023, reflected these dynamics. They coincided with rising energy prices across Europe and the faltering of Ukraine’s strategic position as promised funds were tied up in the US Senate.Translating citizens’ dissent into a direct challenge to the war effort depends on the supply of political opposition. And whether owing to deals and agreements between political leaders, ideological predisposition or a sense of responsibility, almost all mainstream parties in Europe continue to support the coalition.Data from a December 2025 EU-VALUES survey, which asked experts to rate observations of fatigue for Ukraine support on a scale from 1 (not at all) to 5 (very frequently), highlights a significant divide between perceptions of elite and public fatigue across Europe. Citizens seem to have become sceptical of supporting Ukraine. But this view does not appear to be shared by European political elites, who largely continue to support the policy.Perceived war fatigue in EU member states There is a significant divide between perceptions of elite and public fatigue over the Ukraine war across Europe. CC BY-NC-ND So far, political opposition to supporting Ukraine has tended to come from radical parties on the far right and far left, such as the Alternative für Deutschland (AfD) in Germany and Podemos in Spain. But the overall picture among radical right parties on supporting Ukraine is mixed. There is similar equivocation among radical left parties. Parties such as Die Linke on the left in Germany and the National Rally on the right in France are deeply divided on the issue.The efficacy of the challenge these parties present is also unclear. On the one hand, spoilers such as former Hungarian prime minister Viktor Orbán and current Slovakian prime minister Robert Fico have proved highly disruptive. They have been accused of holding EU sanctions packages on Russia hostage.On the other hand, radical right parties have often remained out of government and where they have come close to power – as with Geert Wilders in the Netherlands – would-be coalition partners have extracted clear commitments not to pull support from Kyiv.The election of Donald Trump as US president in November 2024 complicated this picture. Trump’s arrival and subsequent freezing of aid raised the costs of supporting Ukraine for European governments, made Ukrainian victory appear less likely and gave succour to the radical right. But his attacks on European trade and security interests placed radical right parties in an awkward position and made a pro-Trump worldview more difficult to sell at home.Shifting battlefield momentumRecent evidence has suggested the battlefield momentum is shifting in Ukraine’s favour. Ukrainian strikes on the Russian energy grid and logistics centres, for example, have been well publicised.In a meeting with Trump on July 28, Ukraine’s president, Volodymyr Zelensky, also seemingly convinced his US counterpart of his ability to win the war. The meeting took place shortly before the Senate voted to approve new sanctions on countries purchasing Russian oil.Such momentum may help to quell dissent among citizens and galvanise western support insofar as it suggests a speedier end to the conflict on terms that would vindicate the actions of coalition members.It is too early to tell how these events will play out. But any reversal of Kyiv’s fortunes bodes well for the ability of western and European leaders to keep their citizens on board with the task of defending Ukraine.Benjamin Martill has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement no. 962533. He is affiliated with Chatham House and the Independent Commission on UK-EU Relations.Adam Holesch is the project manager of the EU-VALUES network. The EU-VALUES expert survey, the results of which are presented in this article, was conducted within the framework of the EU Research and Education Network on Foreign Policy Issues: Values and Democracy (EU-VALUES), co-funded by the European Union under Grant Agreement No. 101127854.