(CNN) -- A legal fight is under way in Pennsylvania that could decide if the socially conservative state legalizes same-sex marriage.
A county clerk in suburban Philadelphia has given nearly 100 same-sex couples marriage licenses, even though the state bans same-sex marriage.
D. Bruce Hanes, the elected register of wills in Montgomery County, has been doing this for about a month, and the state Department of Health is now taking him to court to try to make him stop.
The case could lead to a reversal of the state's version of the federal Defense of Marriage Act, or DOMA, if a judge were to side with Hanes in finding that the ban on same-sex marriage contradicts the state's constitution.
In June, in the case U.S. v. Windsor, the U.S. Supreme Court struck down a key part of DOMA, which defined marriage as only between a man and a woman.
Hanes told CNN that about four weeks ago, he was approached by a lesbian couple wanting a marriage license. Instead of immediately saying "no," Hanes and his solicitor reviewed the state's constitution and decided that language about civil rights, happiness and liberty applied to same-sex couples who want to get married.
"We've either got to change the constitution -- permit discrimination on the basis of sex, permit civil rights to be frustrated -- or change the interpretation of that marriage act or change the marriage act. You can't have it both ways," he said.
Hanes has received dozens of thank-you cards, and his office benches are filling up with same-sex couples driving from across the state to get marriage licenses.
But not everyone is on board.
The state filed a petition to make him stop, citing a law passed by the state legislature in 1996 that defines marriage as "between one man and one woman."
At least one lawmaker says Hanes has gone rogue.
"He's a lowly elected official in a county office who is not elected to set policy, but to administer the law as it's been passed," state lawmaker Daryl Metcalfe, a Republican, said Friday. "For a man to start violating the law as he has and commit such a lawless act should be offensive to everyone, no matter what side of the issue you're on."
Metcalfe says he believes the marriage licenses are invalid.
"It doesn't matter how many licenses he issues, they're not worth the paper he's printing them on," he said.
He also said he's drafting legislation to have the state's attorney general, Kathleen Kane, impeached because she said she believed she couldn't defend the state's version of DOMA. His legislation will be introduced when the state legislature returns in September. Metcalfe is also calling for Hanes to be impeached and says he's gotten a lot of support.
The petition filed by the Department of Health states that Hanes is in "direct defiance" of that law and that he "risks causing serious and limitless harm to the public."
Kane is not commenting on the case, since her office isn't handling the petition. But earlier this year, she said she came to the same conclusion as Hanes: The state's version of DOMA conflicted with the state constitution.
"DOMA is wholly unconstitutional. It cannot be fixed," she said in early July when the American Civil Liberties Union sued Pennsylvania after the U.S. Supreme Court ruled on the Windsor case.
Danny Cevallos, a prominent Pennsylvania civil and criminal attorney, says this is exactly the kind of case that could end up deciding the fate of same-sex marriage in the state.
Laws, he said, are made this way all the time.
"The issue is going to be whether or not a reading of the constitution can be read to override the state law ban on marriages," Cevallos said. "The state Supreme Court in Pennsylvania could review this and strike down the state ban."
In the meantime, it's unclear whether same-sex couples with marriage licenses in the state would qualify for benefits.
But for now, Cevallos says, Pennsylvania has become the 14th state to have legal same-sex marriages.
Hanes says he doesn't see himself as a crusader -- just an elected official doing his job.
"In the ordinary course of business, two people are coming into my office, sitting on a bench, waiting to get a marriage license, and they're getting those marriage licenses regardless of their gender," he said. "This is the way it ought to be, and that's the way I would like it to be."
One thank-you note that arrived at his office reads, "If possible I would like to have your autograph."
"That's interesting," Hanes said. "I haven't done that."