ANNAPOLIS, Md. — Maryland’s Democratic Governor Martin O’Malley introduced legislation Monday evening aimed at legalizing same-sex marriage in Maryland, making good on his 2010 re-election campaign promise to work toward enacting marriage equality while in office.

According to aides, O’Malley’s bill offers broad protections for groups that would not want to perform or honor same-sex marriages.

The governor, his staff and advocates worked throughout the day to hammer out language detailing religious protections, reported The Baltimore Sun, distributing new legislative language just moments before the session began at 8 p.m. ET.

In an informal briefing with reporters earlier Monday, O’Malley said his bill would make religious protections “a little clearer” than they had been in last year’s version of the measure. He said he hoped the changes would lead to “additional support.” 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 Baltimore Sun

O’Malley said he hoped the changes would lead to “additional support,” and has invited gay advocates and religious leaders to a breakfast at his official residence, Government House, on Tuesday morning and is expected to further brief the news media on his proposal.

A same-sex marriage bill passed last year in the state Senate and is expected to do so again. But the measure fell short in the House of Delegates, where the legislation attracted 59 co-sponsors — four of them later dropped off. Seventy-one votes are needed for passage in the House chamber.

O’Malley announced last July that he was prepared to lead a more aggressive campaign to legalize same-sex marriage, and said he would borrow elements of the strategy used by New York Gov. Andrew Cuomo (D) and marriage equality supporters in the Empire State to sponsor and pass a gay marriage bill in Maryland’s 2012 legislative session.

In October, O’Malley released a video in which he called for balancing religious freedom with the freedom to marry.

“As a free and diverse people of many different faiths, we choose to be governed under the law by certain fundamental principles, among them, equal protection of the law for every individual and the free exercise of religion without government intervention,” O’Malley says in the video.

“The legislation we plan to introduce in the 2012 legislative session will protect religious freedom and equality of marital rights under the law,” he said.

O’Malley has downplayed expectations that his bill would have more delegates on it this year.

“We haven’t worked so much on cosponsors as addressing the concerns that kept it from passing last time around,” O’Malley said.