U.S. and European regulators are struggling with sovereign-debt crises, stalling economies and other issues, driving changes to banks' capital standards, which are meant to fortify the broader system. "The game on the ground has changed in Europe and the U.S.," said V. Gerard Comizio, a former lawyer at the Treasury Department. "The realists in Europe realized that their banks cannot raise the capital they'd need to comply. U.S. banks have reversed course and are more assertively fighting against it. The future of Basel III looks less certain now than it did when it was agreed to."