Why Does the Euro Remain So Resilient?

FORTUNE -- Every week for the past three months, headlines in financial newspapers have announced that the eurozone is on the brink of disaster. The casualties, thus far, include the leaders of Italy and Greece; Dexia, the French-Belgian bank, and most recently MF Global, the American brokerage. Despite last week's coordinated actions by central banks to free up transatlantic capital, some analysts still forecast a calamitous outcome. Standard and Poor's move to put 15 eurozone countries on notice for a possible debt downgrade doesn't help.