The 27 EU presidents and prime ministers, who are making final preparations ahead of their meeting next Monday and Tuesday, have a new spring in their step, despite the war in Ukraine, which is approaching its 100th day. Notwithstanding that traumatic conflict — as well as the ongoing coronavirus pandemic, which could yet worsen again this autumn and winter, and Brexit-related problems over the Northern Ireland protocol — a significant number of European politicians sense there is now a historic window of opportunity to drive forward the integration project. While this upbeat mood may be surprising to some, crises have often been key moments of opportunity for the EU leaders that seek “ever closer union.” The period since Russia’s invasion of Ukraine has been a truly historic one for the continent, with unexpected unity among the 27 states around several big waves of sanctions against Moscow, plus significant movement forward on internal European projects in areas ranging from defense to energy. However, this current window of opportunity did not begin in February; it actually extends back to at least the onset of the COVID-19 crisis in 2020. The pandemic led to a number of genuine breakthroughs that would not otherwise have happened, including the €750 billion ($801 billion) coronavirus recovery fund that committed the bloc to the principle of mutualized debt as a funding tool for the first time in its history, potentially paving the way for greater future supranational powers of taxation and a more federalized continent. While this scheme was primarily economic in nature, it represents a major political milestone in the postwar history of European integration. This crisis-driven window of opportunity has been intensified by Russia’s invasion of Ukraine. And just as during the pandemic, there have been some key developments that would not otherwise have occurred. One example is energy policy, where significant change is underway, provoked by the fact that Russia’s war chest is refilled on a daily basis with European money thanks to its payments for oil and gas. At the time of the invasion, the EU depended on Russia for about 40 percent of its natural gas and a quarter of its oil imports, with the 27 member states paying about €1 billion a day to Moscow for those supplies.Last week, the EU launched its new “REPowerEU” plan with a headline goal of cutting Russian gas out of the European energy equation entirely before 2027, and by two-thirds before the end of the year. There are also hopes in Brussels that a new oil embargo will be announced this month. The European Commission claims that 95 percent of the REPowerEU plan’s €300 billion in financing will go into the energy transition, speeding up the Green New Deal. Moreover, the target of green power in the EU’s energy mix has been raised to 45 percent by 2030 from its current target of 40 percent, via measures such as simplifying the permit process for renewables projects. Brussels is enabling increased natural gas purchases from nations like the US, Egypt, Israel and the Gulf states, producing more biomethane and having coal and nuclear plants run longer hours. Moreover, it also wants to boost the EU’s binding 2030 energy savings target to 13 percent from 9 percent and to cut oil and gas demand by 5 percent by getting people to use less energy. Another example of the rapidly shifting sands is defense, with both Finland and Sweden having applied to join NATO, while Denmark is reviewing its opt-out clause that has so far kept it away from the EU’s common defense policy. Brussels is also pushing forward with a European Defence Action Plan, as strategic military autonomy tops the EU’s political agenda. On the international front, one other factor that has enabled the EU to think more boldly is the presidency of Joe Biden. His time in office has seen a significant change in the approach from Washington compared to the Donald Trump era. Some tensions remain in transatlantic ties and a mooted US-EU trade deal is not close to being realized. However, the tensions so evident from 2017 to early 2021 have largely been sidelined, at least until 2025, when a Republican (possibly even Trump) could claim the White House. This underlines that, while EU leaders currently feel on the front foot, that may not remain the case if more storm clouds gather. Little can be taken for granted and the decisions taken in the coming months will help define the bloc’s longer-term political and economic character in the face of more new challenges, both domestic and foreign, which are on the horizon. • Andrew Hammond is an Associate at LSE IDEAS at the London School of Economics.