Same-sex marriage is already legal in New Mexico, if Santa Fe city officials are to be believed.

Citing an ABC News-Washington Post poll this week that showed growing support for gay marriage nationally, Santa Fe Mayor David Coss, City Attorney Geno Zamora and Councilor Patti Bushee announced their support for gay marriage Tuesday and recommended that city clerks begin doling out marriage licenses to couples, regardless of gender.

"Marriage law in New Mexico is gender-neutral and does not define marriage as between a man and a woman," Zamora said in a statement from Santa Fe city government. "New Mexico already recognizes valid marriages performed in other states between same-sex couples; it would violate our state's constitution to deny equal rights in our own families."

Coss is a Democrat, but his coming out in favor of gay marriage echoes the sentiments of Sen. Rob Portman, R-Ohio, because he, too, has a gay child. Portman announced his support for marriage equality last week, saying he wanted his gay son to enjoy the same opportunities as his other children.

Some marriage-equality activists see the Santa Fe mayor's declaration as a positive step forward and others worry it could end in heartbreak for the couples that heed the mayor's call to marry.

Gregory T. Angelo, executive director of pro-gay rights Republican organization Log Cabin Republicans, compared Santa Fe to San Francisco in 2004 when then-Mayor Gavin Newsom ordered county clerks to give marriage licenses to gay couples, resulting in more than 3,000 marriages that were invalidated by California Supreme Court six months later.

"I think this could be a mess," Angelo said today. "It's also unfair, I think, to gay and lesbian couples who might obtain marriage licenses through this initiative, because they would not have the guarantee of protections that would be afforded to them if this was handled on the state level."

But law professor Andrew Koppelman of Northwestern University believes this is a straightforward case. For county clerks to refuse marriage licenses to same-sex couples would be illegal discrimination, in his view.

"For a long time, this argument was a loser because people presupposed without any legal authority to support it that same-sex marriage was impossible. But that has changed," Koppelman said today. "This argument that same-sex couples already have a right to marry under existing law as a legal argument could very well be a winner in court."

Stuart Gaffney of Marriage Equality USA is cautiously optimistic about Mayor Coss' call to county clerks.

Gaffney recognized the connection between the San Francisco case, but said those invalidated marriages all paved the way for the Supreme Court case on same-sex marriage being heard next week.

"Whether people are able to finally say, 'I do,' in Santa Fe or across New Mexico at this moment, I can't say for sure. But it's part of the process that is bringing marriage equality closer every day," Gaffney said.

But Gaffney, who married his husband in California before the 2008 passage of Proposition 8, warned that couples who take the mayor up on his offer are opening themselves up to more than just the bliss of married life.

"It can be heartbreaking for couples to see their marriages come and go, so I certainly would not advise anyone to enter into a marriage that may become a test case, unless they're ready to make that part of their marriage vows," Gaffney said. "I would ask them to consider it very carefully."

Gaffney told ABC News in February that activists "have never been more hopeful" about the future of same-sex marriage in America. He reiterated that optimism today.

"There's no question that we're going to see it in our lifetimes, it's just how much longer do we have to wait," he said.

Ultimately, same-sex marriages in New Mexico could face opposition from New Mexico Republican Gov. Susana Martinez.

Martinez has gone on record against legalizing same-sex marriage, as recently as late February.