Europe's debt can be a lesson for U.S.

First Greece. Then Ireland. Now Portugal.

It's not surprising that yet another of its troubled economies has sought a bailout from the European Union. Like the other two, Portugal will get more than $100 billion in loans and be forced to embrace severe austerity -- which will pummel its economy and thus make its debts even harder to pay.

The truth is, all three countries are broke, and the day of reckoning is only being postponed. Since all are likely to default down the road, a lot of needless pain could be avoided if all parties faced the music now. The much larger economy of Spain, feared by some to be next in line for trouble, looks safe, at least for the moment.

But like prior turmoil in Europe -- a couple of world wars come to mind -- we can't pretend this has nothing to do with us. Europe's problems are the result of a collision between a unified currency and disparate national budgets. Portugal, for instance, no longer has a currency of its own to devalue as a goad to recovery.

Yet the handwriting on the wall can nonetheless be read from across the Atlantic: Nations can't keep living beyond their means. Sooner or later, mounting debt makes lenders nervous. They start charging higher interest to roll over your debts, which makes them ever harder to sustain, let alone repay. Eventually, they may refuse to lend you anything at all.

From Nassau County to Albany to Washington, it's a message worth heeding.