For the first time in a generation, the theme of this year was the liberal order’s vulnerability, not its resilience. 2015 was a memento mori moment for our institutions — a year of cracks in the system, of crumbling firewalls, of reminders that all orders pass away.

This was especially true in Europe, where for generations the parties of the center have maintained a successful quarantine against movements that threatened their dream of continental integration — be they far-right or far-left, nationalist or separatist.

On the Eurozone’s periphery, in Greece and Hungary and now in Poland, that quarantine is dead. But in 2015 it began to weaken in the European core. Elections in Great Britain empowered Scottish Nationalists, handed the Labour Party back to crypto-Marxists, and raised the odds that the United Kingdom could depart the European Union or dissolve. Elections in France kept Marine Le Pen’s National Front out of power — but by a narrower margin than ever before. Elections in Spain empowered both the populist left and Catalan separatists. And in Sweden, that blessed end-of-history paradise, the most popular political party was suddenly the Sweden Democrats, whose roots are in homegrown fascism.

Europe’s extremes gained, in part, because in 2015 the center was unusually feckless. Angela Merkel’s decision to open Germany’s borders to a million Middle Eastern refugees earned her the praise of her globalist peers. But it also pushed a fast-forward button on long-term trends threatening the liberal project in Europe — the challenge of Islam, the pressure of migration from Africa, the danger of backlash in countries with little experience of mass assimilation.