If this fragmentation is everywhere enfeebling to governments, in Britain—with its traditional two-party system, majoritarianism and, at the apex, all-powerful prime minister—the effect is traumatic. The worries about presidential government that attended Tony Blair’s thumping majorities—the last secured in 2005—now seem like the naive cares of a distant age. Constrained by coalition rule—which Mr Cameron, to his credit, remains more positive about than most Tories—massive public debt, a rebellious party and the devolution that Mr Blair set in motion, he has occupied an office vastly diminished. Sometimes, to his cost, he has seemed to forget this. Thus the hubris he displayed in failing to win parliamentary support for air strikes on Syria; as a result, he has all but forfeited the prime minister’s centuries-old right to order the country to war. Thus his rashness in allowing Scotland’s nationalists to set the terms of a referendum which was the most dramatic event of his premiership, and in which Mr Cameron was a virtual bystander. Thus, too, it may prove, his willingness to commit Britain’s EU membership to a referendum on an assumption that good sense and his own powers of persuasion can preserve the status quo. The mismatch between Mr Cameron’s strong personal ratings and his uncertain prospects does not support that view.