When the leaders of 20 nations met in Washington in November to face down a grave economic crisis that imperiled them all, the air was filled with promises of a new era of global regulation intended to match a new era of global risk. “There ought to be some low-hanging fruit we can all agree on,” Senator John Kerry, the chairman of the Senate Foreign Relations Committee, said on Monday. He spoke after a week of consulting with foreign leaders and hearing European complaints that Americans started this and now are less interested in creating the rules to prevent a...