The long nineteenth century ended badly for everyone, but radicals were left especially black and blue and battered. This is how we picture Europe’s revolutionary men and women in the late summer of 1914: scales ripped from their eyes, mouth agape, shocked and awed by the apocalypse of the “century of progress.”

For Lenin, who would emerge from this catastrophe as one of the leading figures of the “age of extremes” (1914–1991), the war both was and was not expected. Along with everybody else in Europe’s fin de siècle, Lenin had been scouring the skies for portents of the end for years. But when it finally arrived, it wasn’t what he had had in mind. War he had anticipated. But not that the German Social Democratic Party (SPD) would approve its government’s request for war credits. The SPD was Europe’s most influential Marxist party and the undisputed leader of the continent’s most powerful left-wing organization, the Second International, which just a few years earlier had officially resolved to oppose any war between European nation states. As Trotsky later recalled, Lenin was so stunned by the collapse of the social democratic movement before the surge of European nationalisms that he thought the news about the SPD’s support for the war must be fake.