Yet pulling the plug on Greece would pose enormous risks, not just to Europe’s economy, but to the whole European project, the 60-year effort to build peace and democracy through shared prosperity. A Greek banking collapse would probably lead Greece to leave the euro and establish its own currency — and if even one country were to abandon the euro, investors would be put on notice that Europe’s grand currency design is reversible.

Beyond that, chaos in Greece could fuel the sinister political forces that have been gaining influence as Europe’s Second Great Depression goes on and on. After a tense meeting with his German counterpart, the new Greek finance minister didn’t hesitate to play the 1930s card. “Nazism,” he declared, “is raising its ugly head in Greece” — a reference to Golden Dawn, the not-so-neo-Nazi party that is now the third largest in the Greek legislature.

What we’re looking at here is, in short, a very dangerous confrontation. This isn’t diplomacy as usual; this is a game of chicken, of two trucks loaded with dynamite barreling toward each other on a narrow mountain road, with neither willing to turn aside. And all of this is taking place within the European Union, which is supposed to be — indeed, has been, until now — an institution that promotes productive cooperation.

How did Europe get to this point? And what’s the end game?

Like all too many crises, the new Greek crisis stems, ultimately, from political pandering. It’s the kind of thing that happens when politicians tell voters what they want to hear, make promises that can’t be fulfilled, and then can’t bring themselves to face reality and make the hard choices they’ve been pretending can be avoided.

I am, of course, talking about Angela Merkel, the German chancellor, and her colleagues.

It’s true that Greece got itself into trouble through irresponsible borrowing (although this irresponsible borrowing wouldn’t have been possible without equally irresponsible lending). And Greece has paid a terrible price for that irresponsibility. Looking forward, however, how much more can Greece take? Clearly, it can’t pay the debt in full; that’s obvious to anyone who has done the math.