House Defeats Gay Marriage Ban Amendment WASHINGTON - The House followed the Senate in decisively rejecting a constitutional amendment banning gay marriage, ending for this year debate on what has become the dominant issue for the Republican Party's conservative base.    The 227-186 vote in the House Thursday was well short of the two-thirds majority needed to advance a constitutional amendment, but fulfilled a promise by backers to get lawmakers on the record on the highly sensitive issue in the run-up to Election Day...