Lawmakers on both sides of the issue are preparing legislation that would add same-sex unions to the roster of contentious matters facing the 2005 General Assembly session.
"I think it's clear that this year, Maryland's in play," said Tres Kerns, a leading opponent of same-sex marriage and co-founder of Take Back Maryland.
The gay marriage issue is not new here. The state has a 32-year-old law defining marriage as a union between a man and woman, and from time to time the General Assembly has considered additional restrictions on same-sex couples.
But in recent years, gay-marriage opponents have viewed Maryland as too liberal on social issues to make more restrictions politically feasible.
But emboldened by the success of anti-gay marriage referendums in 11 states in November, opponents of same-sex unions expect to push for a state constitutional amendment banning gay marriage - or at least a restatement of current law making it clear to the courts that the legislature is against the idea.
"National momentum can only go so far," said Carrie Gordon Earll, a spokeswoman for Focus on the Family, a conservative lobbying group. "Ultimately it comes down to the people on the ground, in their counties, putting pressure on their legislators."
On the 10 Christian radio stations in the state where the group airs its broadcasts, it is urging listeners to join the Jan. 27 rally.
Organizers predict the "marriage protection" gathering will attract tens of thousands of supporters to put pressure on the legislative committees that bottled up a similar measure last year.
For that grass-roots strategy to work, the public response would have to be overwhelming. Even the most ardent supporters of a constitutional amendment acknowledge that the legislature is not amenable to the idea.
Del. Joseph F. Vallario Jr., the Prince George's County Democrat who leads the House Judiciary Committee, said he was unlikely to support an amendment for both logistical and political reasons - even though he personally opposes gay marriage.
First, he pointed out, amendments are usually considered only in election years. Second, he said, Maryland law adequately defines marriage as a union between a man and woman, so there is no need for a redundant amendment. He said he would consider an amendment only if the law appeared to be in jeopardy from the courts.
Nor is he likely to be swayed by demonstrations. "No. I won't do it just because a lot of people want it. That's not the way we work," he said.
Still, Vallario said he expects to hold a hearing on the amendment and bring it to a vote in committee.
"People in the state ought to be able to decide for themselves," said Del. Charles R. Boutin, a Republican representing Harford and Cecil counties who plans to sponsor the amendment again this year.
Although it's the most extreme, Boutin's measure is one of at least three proposed restrictions on same-sex unions being drawn up. Another would bar gay couples from adopting children, while a third would reiterate the 1973 law defining marriage and ensure that Maryland will not recognize gay marriages legalized out of state.
Only Massachusetts allows same-sex marriages - the result of a state Supreme Court decision - while Vermont law allows civil unions, which confer some of the legal benefits of marriage on same-sex couples without giving the relationship the same status.
They also saw the Illinois Legislature's decision to buck the national trend by approving a bill last week banning discrimination against gays and lesbians.
To them, Jan. 27 will be an opportunity to offer an alternative vision of same-sex unions and portray the gay-rights movement as the modern equivalent of the civil rights and women's equality movements.
"We have a lot more work to do to get it out to people that we're not the bad guys," said the Rev. Harris Thomas, founding pastor of the Unity Fellowship Church of Baltimore.
Gay-rights organizers say their event will be held in a church and include clergy who support either gay marriage or legislation extending the rights of gay couples.
The setting and presence of religious leaders are intended to show that "we have truth and justice on our side," said Dan Furmansky, executive director of Equality Maryland.
Though the public events are significant to the legislative strategy of both sides, their underlying purpose is to sway voters who are undecided or confused by the issue. According to the Sun poll of 800 likely voters conducted Jan. 4 and 5, there is still room for convincing.
When asked whether they favored or opposed civil unions - which would extend some benefits to gay and lesbian couples short of full marriage - 42 percent were in favor, 48 percent were opposed and 10 percent were undecided.
But the margins among different groups shows that the issue doesn't always follow traditional social fault lines.
Voters under 35 supported civil unions by 53 percent to 39 percent. Those over 65 strongly opposed them, 57 percent to 33 percent.
Republicans, who used the issue nationally to increase turnout in the presidential election, opposed civil unions in Maryland, 66 percent to 26 percent.
Democrats were slightly in favor, with 47 percent expressing support and 42 percent opposing. Independents supported civil unions by a 52 percent-to-38 percent margin.
Among whites, opinion ran against civil unions, 47 percent to 42 percent. The margin was significantly wider among African-Americans, who opposed civil unions by a 58 percent-to-28 percent margin.
African-American clergy have been among the primary organizers of the marriage protection rally.
At a gathering of pastors against gay marriage in Rosedale's Mount Pleasant Baptist Church last fall, organizers showed a video produced by the Traditional Values Coalition that condemned the analogy gay-rights advocates drew in 1993 between their march in Washington and the 1963 civil rights march on Washington.
Gay-rights lobbyists said they don't expect to see legislation that would specifically create civil unions this session.
In July, nine gay couples filed a lawsuit in Baltimore Circuit Court challenging Maryland's state law banning gay marriage. They claimed it violates constitutional protections of due process, equality and prohibitions against sex discrimination.
It was the existence of that lawsuit - still to be resolved - that motivated social conservatives such as Del. Donald H. Dwyer Jr., an Anne Arundel Republican, and Doug Stiegler, executive director of the Family Protection Lobby, as well as clergy to begin scouting for support last fall.
They said the effort received a boost in November, when voters in all 11 states considering constitutional amendments banning gay marriage approved them.