WASHINGTON — The House yesterday rejected a constitutional amendment to ban gay marriage, ending for another year a congressional debate that supporters of the ban hope will still reverberate in this fall’s election.

The 236–187 vote for the proposal to define marriage as a union between a man and a woman was 47 short of the two-thirds majority needed to advance a constitutional amendment. It followed six weeks after the Senate also decisively defeated the amendment, a top priority of social conservatives.

But supporters said the vote will make a difference when people got to the polls in November.

“The overwhelming majority of the American people support traditional marriage,” said Rep.Marilyn Musgrave, a Republican of Colorado, sponsor of the amendment. “And the people have a right to know whether their elected representatives agree with them.”

Opponents dismissed the proposal as both discriminatory and legislatively irrelevant because of the Senate vote. The measure is “all for the purpose of pandering to a narrow political base.” Rep.Tammy Baldwin, an openly gay Democrat from Wisconsin, said. “This hateful and unnecessary amendment is unworthy of our great Constitution.”

The marriage amendment is part of the “American values agenda” the House is taking up this week that includes a pledge protection bill and a vote on President Bush’s expected veto of a bill promoting embryonic stem cell research. Mr. Bush has asked, and social conservatives demanded, that the gay marriage ban be considered in the runup to the election.