The vote was 219-206 on the legislation that Democrats trumpeted as a move to bring fuller disclosure to shadowy campaign ads and Republicans attacked as an unconstitutional restriction on free speech.
In a statement, President Barack Obama praised the bill, although he said, "I would have preferred that it include no exemptions." He urged quick action in the Senate, where Majority Leader Harry Reid has pledged to seek a vote but strong Republican opposition make its prospects uncertain.
At the juncture of the First Amendment and partisan politics, the measure produced an unlikely alignment among the very groups it was intended to regulate.
Organizations as diverse as the American Civil Liberties Union and Sierra Club on the left to the Chamber of Commerce and the National Right to Life Committee on the right opposed it. The NRA was officially neutral - and drew a jab from House Republican Leader John Boehner of Ohio because of that.