People walk in front of a damaged shopping mall following an air attack in Kyiv on October 19, 2026, amid the Russian invasion of Ukraine. —Oleksii Filippov-AFP-Getty ImagesIn the fifth year of their war on Ukraine, Russian forces are making little headway on the battlefield. And Ukraine has used drones to bring the war to cities across Russia, including Moscow. That is bad news for President Vladimir Putin of Russia, whose personal standing is tied directly to this war. Putin is now determined to escalate, not just against Ukraine but also against the Europeans who have done so much to keep Kyiv in the fight.He sees opportunities ahead. The Ukrainians are running low on Patriot interceptors and other air defenses, giving Russian missiles and drones a better shot at more effectively striking targets across Ukraine, including the infrastructure needed to keep the lights and heat on as winter approaches. Putin also knows that 10 European Union member states will hold elections in 2027. He hopes that by waging hybrid warfare—disruptive sabotage attacks on E.U. and NATO members—he can turn European voters and some of their leaders against continued support for Kyiv.European officials are bracing for three forms of Russian aggression. They have already seen a substantial number of Russian drones stray into NATO airspace, a byproduct of their growing use in the war and of the technologies both Russian and Ukrainian forces use to jam navigation systems. The Europeans also see deliberate drone incursions, sabotage strikes such as the foiled Aug. 4 attack on a Ukrainian cargo plane at Leipzig airport, and even assassination plots. These operations serve several purposes: to test NATO responses, disrupt the supply of weapons and equipment to Ukraine forces, and raise the perception of rising costs for Europe’s continued support for Kyiv. Finally, there is a low-risk possibility that Moscow might try to destabilize NATO countries such as Estonia and Latvia by mobilizing ethnic Russians within their borders and deploying the “little green men” (Russian troops without uniforms and identifying insignia) used to seize Crimea in 2014. Such an operation would test NATO’s will to defend its borders.NATO officials are well aware they must prepare for Russian provocations that fall short of forcing alliance members to invoke Article 5, the alliance’s collective defense provision. European officials are developing a new National Security Strategy with an “emergency protocol” under which the European Commission can bring together heads of state to respond quickly to Russian aggression. Retaliatory steps could include significant new sanctions and the deployment of European troops, weapons, and military hardware much closer to Russia’s borders. Europeans also control more than $225 billion in frozen Russian assets that could be seized. The hope is that clearer, better coordinated European plans for response will make Putin more careful about actions that could precipitate a crisis by inflicting major economic damage or killing European civilians, even inadvertently. The message is blunt: Europe is united, prepared to respond and committed to Ukraine. Further escalation won’t change the European position. European leaders aren’t just managing Putin’s expectations. They are also demonstrating to President Donald Trump that they are working to handle threats from Russia without relying on NATO—and therefore American leadership and taxpayer dollars. That said, they are presenting this National Security Strategy as a complement, not an alternative, to NATO. They know a credible response from the alliance remains essential to deterring Putin’s most aggressive plans. European officials must act fast. They hope not only to help Kyiv weather Russian attacks in the coming winter, but also to better protect their own physical and cyber infrastructure. They also need to improve intelligence gathering and sharing, which is critical to responding swiftly and forcefully to new Russian moves. And they know they must have those preparations in place by the end of this year.