A century ago, Europe tore itself apart in what was, for a time, known as the Great War — four years of death and destruction on an unprecedented scale. Later, of course, the conflict was renamed World War I — because a quarter-century later Europe did it all over again.

But that was a long time ago. It’s hard to imagine war in today’s Europe, which has coalesced around democratic values and even taken its first steps toward political union. Indeed, as I write this, elections are being held all across Europe, not to choose national governments, but to select members of the European Parliament. To be sure, the Parliament has very limited powers, but its mere existence is a triumph for the European idea.

But here’s the thing: An alarmingly high fraction of the vote is expected to go to right-wing extremists hostile to the very values that made the election possible. Put it this way: Some of the biggest winners in Europe’s election will probably be people taking Vladimir Putin’s side in the Ukraine crisis.

The truth is that the European project — peace guaranteed by democracy and prosperity — is in deep trouble; the Continent still has peace, but it’s falling short on prosperity and, in a subtler way, democracy. And, if Europe stumbles, it will be a very bad thing not just for Europe itself but for the world as a whole.