The murder trial of a Kentucky woman could become an important gay rights case after the woman's partner in a civil union was asked to testify at the murder trial.
The case of Bobbie Jo Clary, who is accused of murdering a man in Louisville in 2011, has turned into an argument over discrimination and rights after Kentucky prosecutors subpoened Clary's partner.
Prosecutors say Clary used a hammer to beat and kill George Murphy, 64, at his home in October 2011, and claim that she shared details of the murder with her partner, Geneva Case, according to ABC News affiliate WHAS.
Clary could get the death penalty if convicted.
Clary, 37, admitted to being with Murphy on the night of his death and stealing his van, police said, but Clary claims she was being raped by Murphy when she grabbed a hammer to fend him off, according to WHAS.
Prosecutors have said at court that Case heard Clary admit to killing Murphy and that Case observed blood on the interior of the van, and that she should testify in court.
Kentucky, like many states, has a spousal privilege law exempting spouses from testifying against one another in court.
Prosecutors said the law does not apply to Clary's spouse because Case is a woman and Kentucky does not recognize civil unions or same-sex marriages. The state passed a law by referendum in 2004 that makes it unconstitutional to recognize same sex marriages or unions.
"The prosecutor here in Kentucky said sorry, Kentucky doesn't recognize those relationships and so we're not going to allow that privilege," said Bryan Gatewood, the attorney representing Case.
The Jefferson County prosecutor's office did not return calls for comment from ABC News. The court overseeing the case, however, has asked the Kentucky attorney general's office to step in and argue the state's law in court.
The state attorney general's office declined to comment on the issues of the case, but said they were reviewing the file to prepare for a hearing scheduled for August.
Case and Clary entered into a civil union in Vermont a decade ago, Gatewood said, before the state had legal marriage for same-sex partners.
"If you look at Vermont's law at the time, they intended the civil union laws to be equal to marriage in all things but name," Gatewood said.
The prosecution subpoenead Case to testify against Clary in Clary's upcoming trial, but Gatewood has filed a motion to quash that subpoena.
"Our argument is that the constitutional amendment (banning same-sex marriage) is unconstitutional and the court should strike it down," Gatewood said.
Gatewood argued during a hearing Tuesday in the Jefferson Circuit Court that the state recognizes other types of unions that are not covered under Kentucky law, including common law marriages from other states, and so should recognize civil unions.
"There's no marriage certificate or ceremony or marriage in common law marriage, but Kentucky recognizes it. If you're going to do it for heterosexual couples but not a civil union from another state, that's a violation of equal protection," Gatewood said.
The judge overseeing the case in the circuit court postponed the matter until the state can present arguments in mid-August, but Gatewood said he is willing to fight the case to the U.S. Supreme Court. He said that if the court strikes down the state constitutional amendment on federal grounds, the case will go to the Kentucky Supreme Court, and from there directly to the U.S. Supreme Court.
He said he was willing to go "as far as we have to go."
"In this case it's very cognizable. You can see the cost to the parties if the spousal privilege is not allowed to be invoked. People ask why is (gay marriage) important. Well there are thousands of rights and protections that come from it," Gatewood explained.