Maryland Voters To Vote On Gay Marriage

From the Baltimore Sun: Activists working to repeal Maryland's same-sex marriage law have collected more than twice the signatures needed for a referendum — likely ensuring that the measure will be on the ballot for voters to decide in November.
The law's opponents submitted 122,481 signatures in favor of a referendum; 55,736 are required. If enough are verified as legitimate, as expected, Maryland will be in the center of a national debate on same-sex marriage, with groups on both sides preparing to spend millions.
The Rev. Derek McCoy, who heads the leading group opposed to the law, called the effort "absolutely exhilarating."
"Marylanders have a right to vote on this issue," said McCoy, executive director of the Maryland Marriage Alliance, after the group dropped off boxes of petitions outside the Maryland secretary of state's office.
The state board of elections has 20 days to review the signatures.
The marriage law would be the second on this fall's ballot. Opponents of a law to allow some illegal immigrants to pay in-state tuition at Maryland universities have won a referendum on that measure. A campaign is under way against a third law, the state's new congressional districting map.
Maryland's Democratic-led General Assembly passed a law in March legalizing same-sex marriage, but it does not go into effect until January 2013. The date was picked to give opponents time for a referendum.
Opponents collected petition signatures in every county in Maryland, according to a report they filed with the state. They found the most in Baltimore County, with 20,363 opposing the law. In Montgomery County, a Democratic stronghold where all but one lawmaker voted for same-sex marriage, 16,611 people signed, the second-highest number.
http://www.baltimoresun.com/news/maryland/bs-md-same-sex-signatures-submitted-20120529,0,5986836.story
According to the paper, the vote will be held on the same day as the presidential election.  The leaders of the anti-gay marriage movement in Maryland are Black, so will this make a difference int he presidential election?  I kind of doubt it as Maryland is as blue as they come but it may put Maryland into play and it will force the Obama campaign to spend money there when they were not planning on it.
Has any state had an election in which they voted in favor of gay marriage?  So, my guess the gay marriage law will be overturned by the voters of Maryland.