The twin political and fiscal disasters of Greece's sovereign debt crisis have spread to Italy, Europe's third largest economy. Prime Minister Silvio Berlusconi's governing coalition has crumbled ahead of a crucial budget vote scheduled for Tuesday, and a key ally has demanded his resignation. Interest rates on Italy's debt rose to 6.47 percent, the highest since the country joined the euro. As Greece negotiates a transitional government, the fate of the euro remains in question. What might this mean for the U.S economy? Joe Nocera,  op-ed columnist for The New York Times, looks at the potential impact.