Is Time Running Out on the Eurozone?

The German Parliament today approved expanded powers for the European Union's main bail-out fund, a big victory for Chancellor Angela Merkel. But with Greece in the throes of protest over austerity measures, there's still concern that the can is being kicked down the road. How much longer will frugal Germans be willing to support other countries they regard as undisciplined spenders? Could Greece still default on its debt? Would that trigger an economic "contagion" threatening the global economy with drastic consequences for the United States?