Growing skepticism about President Joe Biden’s reelection chances has European leaders heading to the NATO summit in Washington confronting the prospect that the military alliance’s most prominent critic, Donald Trump, may return to power over its mightiest military. NATO – made up of 32 European and North American allies committed to defending one another from armed attack – will stress strength through solidarity as it celebrates its 75th anniversary during the summit starting Tuesday. Event host Biden, who pulled allies into a global network to help Ukraine fight off Russia’s invasion, has called the alliance the most unified it has ever been. But behind the scenes, a dominant topic will be preparing for possible division, as the power of far-right forces unfriendly to NATO grows in the U.S. and other countries, including France, raising concerns about how strong support will stay for the alliance and the military aid that its members send to Ukraine. At the presidential debate, Biden asked Trump: “You´re going to stay in NATO or you´re going to pull out of NATO?” Trump tilted his head in a shrug. Biden’s poor debate performance set off a frenzy about whether the 81-year-old president is fit for office or should step aside as the Democratic presidential candidate. Even before the debate, European governments were deep in consultations on what they could do to ensure that NATO, Western support for Ukraine and the security of individual NATO countries will endure should Trump win back the presidency in November and temper U.S. contributions. Some Americans and Europeans call it “Trump-proofing” NATO – or “future-proofing” it when the political advances of far-right political blocs in Europe are factored in. This week’s summit, held in the city where the mutual-defense alliance was founded in 1949, was once expected to be a celebration of NATO’s endurance. Now, a European official said, it looks “gloomy.” There are two reasons for the gloom: Russian advances on the battlefield in the months that Trump-allied congressional Republicans delayed U.S. arms and funding to Ukraine. And the possibility of far-right governments unfriendly to NATO coming to power. The official spoke to reporters last week on condition of anonymity to discuss private conversations among governments. Rachel Rizzo, a senior fellow on NATO with the nonpartisan think tank the Atlantic Council, says she has a blunt message for Europeans: “Freaking out about a second Trump term helps no one.”