The Republican-led campaign for a constitutional amendment to ban same-sex marriage in Maryland suffered a major setback Thursday, when a House committee killed legislation that was intended to put the measure before the voters in November.

The House Judiciary Committee voted unanimously against the proposed amendment, with even its most ardent supporters voting against it after Democrats amended the bill to allow civil unions with full marriage rights between gay couples.

Republican legislators said the fight is not over, and said they will continue the push for the ban on gay marriage in the state Senate.

"Thank God there is a Senate," said Republican Delegate Michael Smigiel.

After the bill was amended, its sponsors, including chief Republican sponsor Delegate Donald Dwyer Jr., removed their names from the measure.

"The bill no longer represents my intent or my will," Dwyer said. "Once again, the Democrats have been up to their dirty deeds and have completely reversed the intent of the bill."

The vote in the committee occurred after Republicans in the House of Delegates were thwarted in an effort to bypass normal procedure and bring the gay marriage amendment to the floor without a committee vote.

Rather than allow the Republicans to try their unusual tactic, House Speaker Michael Busch, a Democrat, gaveled the House session to a close a few minutes after opening ceremonial and procedural duties were finished.

Republicans objected that the Democratic leadership's abrupt move was unprecedented.

"When the rules of the house have been breached by the speaker himself, there are no rules at all and there is no longer any integrity of the institution," Dwyer said.

Later, aides to Gov. Robert Ehrlich joined the condemnation of the Democratic leadership.

"Today is a sad day for Maryland," said Ehrlich spokesman Greg Massoni. "Fifteen people decided to make a decision for 5 million people by not allowing the vote on the floor and the vote in November."

At the heart of the Republican effort was the assumption that if the full House was forced to cast a recorded vote on the measure, many more delegates of both parties would feel compelled to vote for it in an election year.

Democrats said that they just wanted to follow the standard legislative procedure and allow the bill to be voted on by the committee.

"We want the process to work as it's always worked," said Democratic House Majority Leader Kumar Barve.

Same-sex marriage has suddenly become the most contentious issue of the 2006 election year session, in the wake of Baltimore Circuit Court Judge M. Brooke Murdock's decision two weeks ago striking down the 1973 law barring the issuance of marriage licenses to same-sex couples. Action on the decision has been stayed pending appeal.

"I think the issue will blow up in Democrats' faces politically," said Republican Delegate Christopher Shank. "I think their failure to act on this issue will cause a very serious action against the Democrats."

Even Democrats are worried about what the gay marriage issue will do to their political chances this year.

"I think Republicans are going to make it a major campaign issue," said Democratic Delegate Kevin Kelly. "I think it is going to bring moderate-to-conservative voters out en masse, and I think they're going to be more inclined to vote Republican.

Capital News Service contributed to this report.