After the sovereign debt, migration, Brexit and pandemic crises (to name but a few), the European Union (EU) again faces a crisis of – as yet – unknown proportions. Putin's war of aggression against Ukraine violates every principle of the European security order that emerged with the end of the Cold War. It also contests the liberal model for organizing societies the EU and its member states have been built around. Amidst these profound challenges the German Chancellor Olav Scholz referred to as ‘Zeitenwende’, politicians and pundits alike call for the deepening of European integration to defend the EU as a liberal integration project. Institutional reforms are deemed indispensable to prepare the EU for the accession of the Western Balkans and Ukraine and build the EU's strategic autonomy in weathering current and future challenges, geopolitical and otherwise. The sovereign debt, mass migration, rule-of-law backsliding and the Covid-19 pandemic have revealed the EU's weakness as a regulatory polity in coping with non-military transboundary crises. Military security pressures might do what the previous crises failed to do – finally push the member states to build up the EU's fiscal and coercive power turning it into United States of Europe.

Even if the treaty reforms necessary for remedial capacity-building were on the cards in the foreseeable future, EU research does not necessarily support the expectation that conferring more power to the EU produces more power of the EU. The problem of the EU's wanting actorness does not lie so much in the weakness of its fiscal and coercive power nor in its decision-making rules and procedures. It is the member states – in the East and the West – prioritizing their national self-interests over realizing shared goals. The Ukraine crisis is a case in point. Despite the persistence of intergovernmental institutions in foreign and security policy, the member states have been remarkably united in supporting Ukraine against Russia's war of aggression.

As in previous crises, the EU has been coping with its first military security crisis by using its regulatory power to facilitate the joint exercise of fiscal and coercive power by the member states. Yet, the outcome of this crisis differs. It has not resulted in a strengthening of the EU's regulatory powers as we have seen it in the Euro crisis. Unlike in the Covid-19 crisis, the member states have not been willing to give the EU more fiscal power to finance the financial assistance for Ukraine either. At the same time, intergovernmental co-operation has not been deadlocked by member states' refusal of solidarity that has derailed joint decision-making in the Schengen crisis. In our previous work on the EU's multiple crises, Thomas Risse and I argued that changes in the EU's identity politics account for the differing outcomes of the Euro and the Schengen crises (Börzel and Risse 2018). In this article, I explore the extent to which the political mobilization of particular identity constructions related to questions of order rather than borders in framing the Ukraine crisis can help explain why member states have upgraded their common interest in supporting Ukraine without granting the EU additional power.

The article starts by conceptualizing supranational institutions and member state solidarity as two separate dimensions of deepening European integration. It then develops an argument that links deepening European integration to identity politics. To empirically illustrate the argument, I analyze the outcome of the EU's Ukraine crisis and compare it to previous crises. The comparison reveals that the member states have been willing to upgrade their common interests without pooling or delegating additional powers though. This outcome differs from the Euro, the Schengen and the Covid-19 crises, in which member state solidarity went hand in hand with a strengthening of supranational institutions – with the exception of the Schengen crisis, which resulted in neither. Mainstream theories of European integration may explain the absence of institutional reform in the Ukraine crisis by insufficient functional pressure to outweigh the high sovereignty costs involved in granting the EU coercive power. It is less obvious, however, how they would account for the willingness of member state governments to unite in their support for Ukraine in the absence of such pressure. The second part of the article therefore discusses whether the explanation for this peculiar outcome can be found in the identity politics involved in Putin's war against Ukraine. Unlike Schengen and similar to Euro and Covid-19, the upgrading of the common interest even by right-wing populist governments has been facilitated by the war being framed in terms of order (who are we) rather than border (who belongs to us). The identity discourse about what community the EU wants to be fostered solidarity amongst the member states in coping with the Covid-19 pandemic, and in the same way, it is generating solidarity with Ukraine in defending its independent nationhood against Russia, including the granting of accession prospects. EU membership, of course, also relates to issues of borders and belonging; questions of order and border intersect, particularly since EU accession is conditional upon the commitment to and compliance with the EU liberal principles for organizing politics and society. Being a European neighbor, Ukraine qualifies for EU membership. Geographic and cultural proximity also accounts for the willingness of Poland to receive millions of Ukrainians. The article concludes by discussing why the identity discourse enabling a far-reaching upgrading of the common interest on security and defense issues has not resulted in a strengthening of supranational institutions.

在经历了主权债务、移民、英国脱欧和流行病危机（仅举几例）之后，欧盟（EU）再次面临着迄今为止规模未知的危机。普京对乌克兰的侵略战争违反了冷战结束时出现的欧洲安全秩序的每一项原则。它还对欧盟及其成员国所建立的社会组织自由模式提出了质疑。在这些被德国总理奥拉夫·肖尔茨称为“Zeitenwende”的严峻挑战中，政治家和专家都呼吁深化欧洲一体化，以捍卫欧盟作为一个自由一体化项目的地位。机构改革对于欧盟为西巴尔干和乌克兰的加入做好准备以及建立欧盟应对当前和未来挑战的战略自主权至关重要，地缘政治和其他方面。主权债务、大规模移民、法治倒退和Covid-19大流行暴露了欧盟作为监管政体在应对非军事跨境危机方面的弱点。军事安全压力可能会起到之前危机未能做到的作用——最终推动成员国增强欧盟的财政和强制力，将其转变为欧洲合众国。

即使在可预见的未来，补救性能力建设所需的条约改革可能会出现，欧盟的研究也不一定支持这样的预期：赋予欧盟更多权力会产生欧盟更多权力。欧盟缺乏行动力的问题并不在于其财政和强制力的薄弱，也不在于其决策规则和程序。东方和西方的成员国将其国家自身利益置于实现共同目标之上。乌克兰危机就是一个典型的例子。尽管在外交和安全政策方面政府间机构一直存在，但成员国在支持乌克兰反对俄罗斯侵略战争方面表现得非常团结。

与以往的危机一样，欧盟一直在利用其监管权力促进成员国联合行使财政和强制权力来应对首次军事安全危机。然而，这场危机的结果有所不同。它并没有像我们在欧元危机中看到的那样加强欧盟的监管权力。与Covid-19危机不同的是，成员国也不愿意给予欧盟更多财政权力来为乌克兰提供财政援助。与此同时，政府间合作并未因成员国拒绝团结而陷入僵局，这种团结导致申根危机中的联合决策脱轨。在我们之前关于欧盟多重危机的研究中， 2018）。在本文中，我探讨了在构建乌克兰危机时，与秩序问题而非边界问题相关的特定身份建构的政治动员在多大程度上可以帮助解释为什么成员国在不授予欧盟额外权力的情况下提升了支持乌克兰的共同利益。

本文首先将超国家机构和成员国团结概念化为深化欧洲一体化的两个不同维度。然后，它提出了一个论点，将欧洲一体化的深化与身份政治联系起来。为了从实证上说明这一论点，我分析了欧盟乌克兰危机的结果，并将其与之前的危机进行了比较。比较表明，成员国愿意提升其共同利益，但无需汇集或授予额外权力。这一结果与欧元、申根和 Covid-19 危机不同，在这些危机中，成员国的团结与超国家机构的加强齐头并进——但申根危机除外，后者两者都没有造成。欧洲一体化的主流理论可能会解释乌克兰危机中缺乏制度改革的原因是，功能性压力不足以抵消授予欧盟强制力所涉及的高昂主权成本。然而，不太明显的是，在没有这种压力的情况下，他们将如何解释成员国政府团结起来支持乌克兰的意愿。因此，文章的第二部分讨论了是否可以在普京对乌克兰战争中涉及的身份政治中找到对这一特殊结果的解释。与申根区不同，与欧元和 Covid-19 类似，即使是右翼民粹主义政府，战争也以秩序（我们是谁）而不是边界（谁属于我们）为框架，促进了共同利益的升级。 。关于欧盟希望成为哪个共同体的身份话语，促进了成员国在应对 Covid-19 大流行方面的团结，同样，它也与乌克兰团结一致，捍卫其独立国家地位，反对俄罗斯，包括授予加入前景。当然，欧盟成员身份也涉及边界和归属问题；秩序和边界问题相互交叉，特别是因为加入欧盟的条件是承诺和遵守组织政治和社会的欧盟自由主义原则。作为欧洲邻国，乌克兰有资格加入欧盟。地理和文化上的接近也是波兰愿意接收数百万乌克兰人的原因。