That clause requires that a state law affecting the affairs of a single municipality can only be passed as long as two-thirds of its local legislative body agrees.

WSJ: Court Nixes Taxi Plan

But just as the American government used the constitution's interstate commerce clause to expand its powers, so the European institutions have exploited single-market rules to extend their responsibilities into such areas as social policy, welfare and the environment.

ECONOMIST: Fit at 50? | The