The governor, his staff and advocates worked throughout the day to hammer out language detailing religious protections. They distributed the new legislative language moments before the 8 p.m. session began.
The language provided Monday night made a few key changes, according to Raquel Guillory, a spokeswoman for O'Malley. She said the bill extended legal protections to leaders of religious groups, while last year's bill shielded only institutions.
The bill also makes clear that religious leaders, not the state, control theological doctrine, Guillory said. And it further limits any punitive actions — like denying government funds — that the state could take against religious organizations for failing to perform same-sex marriages.
"It is a clarification effort," Guillory said.
O'Malley said he was not sure if the changes would result in more delegates putting their names on the bill.
"We haven't worked so much on cosponsors as addressing the concerns that kept it from passing last time around," O'Malley said.
He has invited gay advocates and religious leaders to a breakfast at Government House on Tuesday morning and plans to further brief the news media on his proposal.
O'Malley last year said he would sign a same-sex marriage bill if it passed the General Assembly, but he did not include such legislation in the administration's package. This year, he has said he will lead the fight for the bill.
Six states and Washington, D.C. currently allow same-sex marriage. On Monday, the Los Angeles Times reported that Washington state's legislature has enough votes to pass the measure there.
Over the past nine months, both sides in the same-sex marriage debate have been active.
To rally grassroots support, Maryland's Roman Catholic bishops in November sent a 16-page statement to churches throughout the state calling on parishioners to act against a same-sex marriage bill and other measures that they say threaten religious liberty.
The coalition supporting same-sex marriage captured headlines in the fall by releasing a steady stream of web videos featuring boldface names including Ravens linebacker Brendon Ayanbadejo, Oscar winner Mo'Nique and former NAACP chairman Julian Bond.
In the weeks leading up to the annual 90-day session, which began Jan. 11, both sides said they were ready to continue the campaign with full force.
Opponents planned a day of prayer that a same-sex marriage bill will fail. They said there would be Sunday sermons focused on traditional marriage and a rally in Annapolis. They united forces under the banner the Maryland Marriage Alliance.
Supporters promised daily phone banks to drum up support for a same-sex marriage bill, and they pledged to bus their troops to Annapolis the day before Valentine's Day. Their coalition is called Marylanders for Marriage Equality.
Last year, a measure that sought to legalize same-sex marriage in Maryland cleared the state Senate but stalled in the House of Delegates. Leaders pulled the bill from the House floor when they realized they didn't have the 71 votes needed for passage.