LONDON  “We told you so.”

When the treaty establishing Europe’s common currency was approved in the early 1990s, Europe’s political and business elite had high hopes that it would bind the Continent’s disparate economies and often bickering nations as never before.

And as the euro made its debut in the early 2000s, there was an outpouring of support from many citizens pleased that they would no longer have to change Spanish pesetas to French francs or Dutch guilders to German marks as they crossed borders from one country to another.

But not everybody was caught up in the celebration. A noisy band of dissenters, many of them economists from outside the Continent, issued a warning: the euro was doomed to struggle, they proclaimed, maybe not immediately but certainly before long. Different countries would pursue such different economic policies, they argued, that it would ultimately place an unbearable strain on the currency and some of its members.

Today, many of those predictions  handily dismissed at the time  are coming true.

For most of 2010, Europe struggled to contain a debt crisis that has prompted investors to drive up the yield on government bonds. And despite two bailouts  for Greece and for Ireland  the anxiety has not dissipated, and attention has turned to other faltering economies like Portugal and Spain.