A Republican lawmaker in Maryland who plans to introduce a civil unions bill startled colleagues this week by resigning from his position as minority leader in the State Senate one week before the scheduled introduction of a same-sex marriage bill.

Sen. Allan Kittleman (R-Howard County) said he decided to withdraw from the minority leader post he held for two years after determining he was not conservative enough for the other 11 GOP senators in the 47-member Senate.

Observers at the state capital in Annapolis said it became clear to Kittleman that his moderate to liberal views on social issues troubled the other GOP senators after he announced plans to introduce legislation allowing civil unions in Maryland for same-sex and opposite-sex couples.

“I’m a social moderate and I wanted to stand up for what I believe in,” the Baltimore Sun quoted him as saying. “It’s more important for me to stay true to my beliefs than it is for me to be the minority leader.”

LGBT advocates pushing for a same-sex marriage bill in the Maryland Legislature had expressed concern earlier this month that Kittleman’s civil unions measure might take away votes from the marriage bill. In other states, lawmakers reluctant to back same-sex marriage have embraced civil unions as a less controversial alternative, saying it provides the same legal benefits as marriage.

But this week, the head of the statewide LGBT group Equality Maryland said she was hopeful that Kittleman’s action would create an opportunity for same-sex marriage advocates to point out the differences between marriage and civil unions and why civil unions don’t provide full protections for lesbian and gay couples.

“This was an incredibly brave and important move on his part to stand by his principles,” said Morgan Meneses-Sheets, Equality Maryland’s executive director.

“And we really thank him for that and we will continue to communicate with him and talk with him,” she said. “We certainly hope we will have his support when the marriage bill comes.”

Meneses-Sheets said the marriage bill is scheduled to be introduced next Tuesday at a time when her organization and most political observers believe supporters of the bill have the votes to pass it in both chambers.

Maryland Gov. Martin O’Malley has said he will sign a same-sex marriage measure approved by the legislature.

Kittleman has not said when he plans to formally introduce his civil unions bill, and he has not released details of its content other than to say it would cover both same-sex and heterosexual couples.

His office said he was not immediately available for comment.

Meneses-Sheets said she doesn’t believe Kittleman was planning to introduce a civil unions bill with the intention of derailing the marriage measure.

“I really think that he truly supports providing protections for gay and lesbian couples and that he’s in a challenging position,” she said. “Clearly, where his party isn’t offering support for that position, he’s standing by his principles.”

Added Meneses-Sheets, “We’re hoping to have those conversations with him and a good open dialogue about why it really needs to be marriage, what the key differences are in both the rights and responsibilities and the important status of marriage in our society.”

The national same-sex marriage advocacy group Freedom to Marry is scheduled to hold a joint news conference with Equality Maryland at the state capital in Annapolis at 11 a.m. on Jan. 25 to announce the official introduction of the marriage bill.

Equality Maryland has announced an increase in its staff to boost its lobbying capabilities on behalf of the bill. The group has begun holding meetings throughout the state to recruit volunteers to engage in grassroots campaigns to rally support for the legislation. Meetings have already taken place in Prince Georges and Montgomery counties, with meetings scheduled Wednesday night in Baltimore and Anne Arundel County.

“They’ve been well attended, and people are incredibly excited and really ready to pitch in every way they can,” said Meneses-Sheets.

The National Organization for Marriage, which is leading efforts to oppose same-sex marriage nationwide, has vowed to spend large sums of money in Maryland to work against passage of a marriage bill.

The group is expected to organize a voter referendum to prevent the bill from becoming law if the legislature passes it and O’Malley signs the measure, setting in motion what some predict will be Maryland’s version of Proposition 8, the California ballot measure that ended same-sex marriage there.