When Donald Trump returned to the White House in January 2025, European countries at first chose appeasement as their preferred U.S. strategy. Faced with a belligerent Washington that threatened to withdraw the American security umbrella, back Russian President Vladimir Putin by brokering an unjust peace in Ukraine, impose punitive tariffs on their exports, and help far-right parties, European leaders convinced themselves that flattery and restraint were the best response. They avoided confrontation, absorbed humiliation, and hoped that by giving Trump enough of what he wanted they could preserve the essentials of the transatlantic partnership. For a time, that strategy seemed to have a logic. Europe still depended on the United States for its security. Ukraine, still at war with Russia, continued to need U.S. weapons and intelligence. European economies seemed too fragile, and European domestic politics too fractured, to risk an outright trade war with Washington.…