A few weeks before Germany’s federal election in late February, Friedrich Merz was forced to backpedal after a daring gambit went awry. His attempt to win votes by forcing through a hardline crackdown on migration had caused a rebellion in his own Christian Democratic party (CDU). Instead of positioning himself as a strong leader, he undermined the entire German political establishment. Merz’s strategy involved breaking a taboo by relying on far-right nationalists to pass legislation for the first time in Germany’s postwar history. The move fractured the country’s normally consensus-driven centrist parties in the Bundestag, sparked mass protests and led...