It can be hard for Americans to understand why Russia’s invasion of Ukraine has touched such a raw nerve in Europe. Even the Biden administration did not expect the European response to be so fast and so furious. The widespread expectation, after all, was that sanctions, coordinated between the United States and Europe, would be rolled out slowly. A batch here, another batch a week later, steadily ramping up the pressure on Russia and imposing incremental punishment for its war of aggression. Instead, the sanctions came crashing down all at once. (From what I heard, individual delegations went into the European Council meeting fearing that other delegations would water the sanctions down, so they promised themselves that they would stand firm. On arriving, they discovered that the opposite was true: everyone wanted to hit Russia hard.) In addition to the sanctions, we saw other sea changes on the continent. Germany, which has been understandably wary of militarization, shredded its post-Cold War doctrine over the weekend, agreeing to send lethal aid to Ukraine and to boost its military spending to two percent of G.D.P. The E.U., for the first time in its history, declared it was sending weapons. Switzerland—Switzerland!—which stayed neutral even through the horrors of World War II, decided to impose sanctions on Russia and freeze Russian assets. 

The White House, which had been laying the groundwork for sanctions and trying to get the E.U. to agree—which is typically like herding cats—was taken aback by the unity and swiftness of the response. Why did Europe react the way it did? “Seeing children using metro platforms as bomb shelters stirs the collective memory of World War II,” a U.S. official told me. “It has made them react with anger and emotion, rather than the logic that usually results in the lowest common denominator.”