Next Monday, a federal court will examine for the first time whether the US constitution allows states to ban gay marriage.
The case, brought by two gay couples who argue that California’s ban violates their constitutional rights, will be heard on January 11th and is expected to last two to three weeks.
It has divided gay rights activists, some of whom say the move is premature and destined to end in failure.
If the case is successful in the San Francisco district court, it is deemed unlikely to succeed in the Supreme Court, where conservative judges have been keen to support all pro-gay initiatives other than marriage.
More than 30 US states explicitly ban gay marriage. If the case is successful, it would reverse years of such legislation.
Gay marriage was legalised in California in May 2008. However, the voter initiative Prop 8 defined marriage as being between a man and a woman in November 2008.
The argument that the ban is unconstitutional was rejected by California’s Supreme Court in May last year.
The gay couples in this case are Kris Perry and Sandy Stier, of northern California, and Paul Katami and Jeff Zarrillo, who live in southern California. They are being represented by Ted Olson and David Boies.
Olson and Boies acted on opposing teams in the Bush v Gore case of 2000. The choice of the pair, with Olson a conservative and Boies a liberal, is seen to make the point that the lawsuit is a human rights issue rather than a case of left against right or Democrat against Republican.
The pair are expected to counter arguments that anyone can marry so long as they choose a partner of the opposite sex. They will also argue that civil unions are not adequate or equal to marriage and that banning gay marriage is not a legitimate government interest.
Tomorrow, US District Judge Vaughn Walker, who is overseeing the case, will hold a pretrial hearing on whether to televise the trial.
Under a new pilot programme introduced last month, cameras will be allowed into courtrooms in Western states during civil, non-jury cases for the first time.
Although the two gay couples and their representatives are keen to have the trial broadcast, gay marriage opponents have said witnesses may be intimidated and lose the right to a fair trial.
Attorney Theodore Boutrous, who is on the Olson-Boies legal team, wrote to Walker arguing that the concerns over intimidation were “utterly unsubstantiated and groundless speculation”.
He added that the case was of “such transcendent importance that every Californian should be afforded an opportunity to view the proceedings”.