Maine, where a same-sex marriage campaign had been working for three years to organize and persuade voters, was attractive. Voters in Washington state had proved their willingness to support gay rights by approving a 2009 measure legalizing domestic partnerships.
In Maryland, Griffin said, "We were still convincing people until the very end."
Freedom to Marry, one of the country's most important gay-rights advocacy groups, was not listing Maryland as a battleground state. The omission, supporters here believed, was scaring off the big national money.
Something had to be done to make the state more attractive to outside donors, McIntosh believed. Far more money would have to be raised locally.
She turned to an unlikely ally: Chip DiPaula. In Maryland, he's best known for helping to elect the state's first Republican governor in a generation when he orchestrated the 2002 victory of Robert L. Ehrlich Jr.
His national contacts, though, came from helping put a different Republican in office. He was CEO of the 2000 Republican National Convention in Philadelphia that nominated George W. Bush for president.
He's also gay — and wanted to see same-sex marriage pass in Maryland.
"National supporters are sophisticated," DiPaula said. "They want to invest their money with precision to secure victory."
With McIntosh's blessing, DiPaula designed a Hail Mary. On Labor Day weekend he spent hours composing a personal appeal to Evan Wolfson, the head of Freedom to Marry.
The message: We can win this. I know because I managed an unlikely campaign before in Maryland. We won then and we will win this time, too.
It worked. Freedom to Marry added Maryland to the list.
"We took the lead on raising early money for three of the four states and left others to do the same in Maryland," Wolfson said in an interview. "When it became clear that others had not stepped up, Freedom to Marry stepped up again. We always thought Maryland could do it."
Coupled with positive polling numbers, better local fundraising, and personal appeals from O'Malley, the freeze among national donors began to thaw. New York Mayor Michael R. Bloomberg gave $250,000. Republican donor Paul Singer gave $250,000. Former NFL commissioner Paul Tagliabue gave $100,000. Brad Pitt gave $25,000.
Freedom to Marry gave $115,000.
In the end, Marylanders for Marriage Equality spent about $6 million, about half what supporters spent in Washington state and Minnesota. Only Maine, a state with less than a quarter of Maryland's population, spent less.
On Oct. 9, a day after opponents began airing their commercials, Marylanders for Marriage Equality debuted its advertising campaign with the message from the two black pastors.
The group spent about $800,000 a week on television time, and Hickman and Coates remained on the air for most of the campaign.
Backlash came swiftly. And it was personal, Coates said.
"It's been tough with some peers and colleagues," he said. "Statements that I'm not a true preacher. I'm not part of the church. A range of judgments and attacks."
He says critics predicted that Coates and Hickman would destroy their ministries.
Since word of the campaign spread, both pastors have had to add services on Sunday to accommodate increased demand.
In a previous version of this story, a single reference to spending by Marylanders for Marriage Equality called the group by an incorrect name. An earlier version misstated the amount donated by Freedom to Marry.