The best thing about the Irish right now is that there are so few of them. By itself, Ireland can’t do all that much damage to Europe’s prospects. The same can be said of Greece and of Portugal, which is widely regarded as the next potential domino.

But then there’s Spain. The others are tapas; Spain is the main course.

What’s striking about Spain, from an American perspective, is how much its economic story resembles our own. Like America, Spain experienced a huge property bubble, accompanied by a huge rise in private-sector debt. Like America, Spain fell into recession when that bubble burst, and has experienced a surge in unemployment. And like America, Spain has seen its budget deficit balloon thanks to plunging revenues and recession-related costs.

But unlike America, Spain is on the edge of a debt crisis. The U.S. government is having no trouble financing its deficit, with interest rates on long-term federal debt under 3 percent. Spain, by contrast, has seen its borrowing cost shoot up in recent weeks, reflecting growing fears of a possible future default.

Why is Spain in so much trouble? In a word, it’s the euro.

Spain was among the most enthusiastic adopters of the euro back in 1999, when the currency was introduced. And for a while things seemed to go swimmingly: European funds poured into Spain, powering private-sector spending, and the Spanish economy experienced rapid growth.