Everyone has a theory about the financial crisis. These theories range from the absurd to the plausible  from claims that liberal Democrats somehow forced banks to lend to the undeserving poor (even though Republicans controlled Congress) to the belief that exotic financial instruments fostered confusion and fraud. But what do we really know?

Well, in a way the sheer scale of the crisis  the way it affected much, though not all, of the world  is helpful, for research if nothing else. We can look at countries that avoided the worst, like Canada, and ask what they did right  such as limiting leverage, protecting consumers and, above all, avoiding getting caught up in an ideology that denies any need for regulation. We can also look at countries whose financial institutions and policies seemed very different from those in the United States, yet which cracked up just as badly, and try to discern common causes.

So let’s talk about Ireland.

As a new research paper by the Irish economists Gregory Connor, Thomas Flavin and Brian O’Kelly points out, “Almost all the apparent causal factors of the U.S. crisis are missing in the Irish case,” and vice versa. Yet the shape of Ireland’s crisis was very similar: a huge real estate bubble  prices rose more in Dublin than in Los Angeles or Miami  followed by a severe banking bust that was contained only via an expensive bailout.

Ireland had none of the American right’s favorite villains: there was no Community Reinvestment Act, no Fannie Mae or Freddie Mac. More surprising, perhaps, was the unimportance of exotic finance: Ireland’s bust wasn’t a tale of collateralized debt obligations and credit default swaps; it was an old-fashioned, plain-vanilla case of excess, in which banks made big loans to questionable borrowers, and taxpayers ended up holding the bag.