The two sides in Maryland's fight over same-sex marriage agree on this: It won't be over until November.
With the state Senate's approval Thursday night of the governor's bill to legalize civil marriage for same-sex couples, opponents are expected to mobilize quickly to gather the signatures to petition the legislation to referendum.
State elections officials say they are already getting calls seeking information on how to start the process. Even the bill's staunchest supporters expect its opponents to easily gather the 55,736 signatures necessary to put the question on the November ballot.
"I think it will only take a few rounds of church signings to get it done," said Carrie Evans, executive director of Equality Maryland and a leading advocate of the legislation.
What happens when the issue goes to the voters is anybody's guess. The last time voters rejected legislation passed by the General Assembly was in 1974, but many observers think it could happen again in 2012.
The most recent poll on the issue, by Gonzales Research and Marketing Strategies, suggested that Maryland voters are divided on the issue. The poll showed voters favoring same-sex marriage 49 percent to 47 percent, but the difference was within the poll's margin of error. And opponents felt more strongly about it.
Derek McCoy, executive director of the Maryland Marriage Alliance, which fought the bill, said opponents believe they will win at the polls, as they have in other states. "We know the numbers. We know the constituents of Maryland. We're pretty confident we can prevail," McCoy said.
The numbers from the Gonzales poll show that same-sex marriage is supported by a comfortable majority of white Marylanders but strongly opposed by African-Americans. With President Obama on the ballot this year, a large African-American turnout is expected.
If the issue goes on the ballot, it would join another referendum measure challenging a bill the legislature passed last year to allow in-state tuition at state universities for illegal immigrants.
That would set up the possibility that voters could strike down two Assembly-passed bills in the same year. In the 1974 referendum, voters rejected a law that would have provided state financial support to nonpublic schools. The last bill petitioned to referendum in Maryland was a measure liberalizing the state's abortion law, which voters upheld in 1992.
Under Maryland's Constitution, now that the Senate and House have passed identical same-sex marriage bills, the petition process can begin — with no need to wait for Gov.Martin O'Malleyto sign his bill into law.
Typically, opponents of a newly passed law would first submit the proposed wording of their petition forms to the State Board of Elections, something they could set in motion as early as Friday.
Once the paperwork is approved, a process that takes a week to 10 days, opponents could begin gathering signatures.
To qualify for the Nov. 6 ballot, opponents of the law will need to gather one-third of the required signatures — 18,579 — by May 31 and the rest by June 30. Opponents may be able to draw on the website set up by Del. Neil Parrott, a Western Maryland Republican, to gather signatures for the in-state tuition bill.
The site makes it easier for people to see exactly how their names are listed on Maryland voter rolls — for instance, whether a middle initial or middle name is used — thus helping to ensure that they sign a petition correctly.
Parrott said this week that he hadn't yet cranked up the site because he was still hoping the measure could be blocked in the Senate. He said no decisions had been made on who would take the lead for General Assembly Republicans, who opposed the measure with the exception of two delegates and one senator.
Traditionally, supporters of a law being challenged scrutinize the signatures for completeness and validity. Equality Maryland's Evans said backers of same-sex marriage will vigorously contest any invalid signatures, but her side doesn't really expect the opponents to fall short.
Evans said same-sex marriage proponents will continue the grass-roots activism that led to victory in the General Assembly. Some national celebrities may join the effort, she said, but the main focus of the campaign will be "Marylanders talking to Marylanders."
"We have organizers on the ground and have been on the ground for months," she said. Evans said her group expects to bring a professional campaign manager on board to lead the referendum fight.
She said most voters really haven't focused on the marriage issue yet.
"We have strong feelings on each side of the issue, but most people have other important things on the top of their minds," she said. Nonetheless, with a string of recent advances in other states, Evans believes voters are becoming comfortable with the idea of marriage equality.
"People are really starting to understand that this is happening in the world and the sky isn't falling," she said.
McCoy is equally upbeat about his side's chances of preventing the law from taking effect next January.
"The burden of proof for redefining marriage for everybody is really on our opponents," he said. "We will be set, prepared and ready."
He said his group will take its time to make sure it follows the letter of the law in gathering signatures.
"Once that happens, I think you'll see us in full gear," he said.
Sun researcher Paul McCardell contributed to this article.