Murray, a strong supporter of same-sex unions, said she will continue to help round up votes to defeat the marriage ban but will oppose any move to bury the proposed amendment with parliamentary tactics.

"My vote is going to be just what it was the last time, but I am not going to move to adjourn," Murray said, speaking with reporters on her way into a Senate session a day after she was elected to succeed Robert E. Travaglini as Senate leader. "I will call for a vote, and I will try to help the advocates get the votes that they need. . . . I think it's important that we vote."

Murray's statement stands in sharp contrast to the vote she took at a Constitutional Convention in November, when she backed a recess motion designed to kill the proposal by keeping it from moving to the 2007-2008 legislative session for a final vote.

Two months later, in the waning moments of the legislative session, the amendment crossed its first hurdle when it won the support of 62 representatives and senators, 12 more than required for approval, after Travaglini, an opponent of same-sex marriage, steered the measure to a quick vote.

The Legislature's next Constitutional Convention is expected to determine the fate of the petition to end same-sex marriage in Massachusetts, which became the only state in the nation to sanction gay marriages after a Supreme Judicial Court decision in 2003. The petition would die if no vote is taken on the proposal in this legislative session.

Kris Mineau -- president of the Massachusetts Family Institute -- which led the petition drive to put the amendment on the ballot, said he found Murray's comments encouraging. He said her statement reflects a realization that her role as Senate president requires her to be even-handed and to make sure a vote is taken on the issue.

"We did not know where she would stand, until she made this [statement]," Mineau said. "I feel she is really stepping up to her total responsibilities as president of the Senate and not just to her own constituents, recognizing that she bears the responsibility that requirements of the constitution are met."

No date has been set for the next Constitutional Convention. Lawmakers who are working to defeat the amendment say that the convention, a joint session of the House and Senate, will convene when they are confident they have the votes to defeat it. As Senate president, Murray has the authority to convene the session.