After two decades in which gay rights moved from the margin to capture the support of most Americans, the Supreme Court justices will go behind closed doors this week to decide whether now is the time to rule on whether gay people have a constitutional right to marry.
For the justices, the issue is not just what to decide, but when to decide it. In the past, the court has been faulted for waiting too long or moving too quickly to recognise constitutional rights.
The justices did not strike down state bans on inter-racial marriage until 1967, 13 years after they had declared racial segregation unconstitutional. Yet in response to the growing women's rights movement, the court in 1973 struck down all the state laws restricting abortion, triggering a national ''right to life'' movement and drawing criticism even from some supporters that the Roe v Wade ruling had gone too far too fast.
Now the justices must decide whether to hear an appeal from the defenders of California's Proposition 8, the 2008 voter initiative that limited marriage to a man and a woman.
At the same session on Friday, the court will sift through several appeals to decide whether legally married gay couples have a right to equal benefits under federal law. Appeals courts in Boston and New York have struck down the part of the Defence of Marriage Act that denies such a right, and the justices are almost certain to take up a case to resolve that question.
The Proposition 8 case, known as Hollingsworth v Perry, presents justices with the more profound ''right to marry'' question. Opinion polls now show a majority of Americans favour marriage equality, and support for it has been growing by about 4 per cent a year. On November 6, voters in Maine, Maryland and Washington approved same-sex marriage, bringing the total to nine states.
Does the shift in public opinion suggest the court should uphold gay marriage now, or wait for more states, perhaps a majority, to legalise it?
Defenders of Proposition 8 say their case ''raises the profoundly important question of whether the ancient and vital institution of marriage should be fundamentally redefined'', and, in this instance, by federal judges.
A federal judge in San Francisco struck down Proposition 8 as discriminatory and irrational. In February, a Court of Appeals affirmed that ruling by a 2-1 vote, ruling the ban on gay marriage violated the constitution's guarantee of equal protection of the laws. The majority relied heavily on a 1996 opinion by Justice Anthony Kennedy that had struck down an anti-gay initiative adopted by Colorado voters.
The decision on whether to hear the case could be a hard call for both the court's conservatives and its liberals. Usually, the justices are inclined to vote to hear a case if they disagree with the lower court ruling.
The most conservative justices - Antonin Scalia, Clarence Thomas and Samuel Alito - almost certainly think the appeal court's ruling was dubious. Scalia, for example, says the ''equal protection'' clause, added to the constitution after the Civil War, aimed to stop racial discrimination and nothing more. He often insists the justices are not authorised to give a contemporary interpretation to phrases such as ''equal protection''.
If the Chief Justice, John Roberts, joins the other three, the conservatives would have the needed four votes to hear the Proposition 8 case.
They may hesitate. To form a majority, they would need Kennedy, the author of the court's two strongest gay rights rulings. His 2003 opinion struck down a Texas anti-sodomy law and said the state could not ''demean'' gays by treating them as second-class citizens. Five months later, the Massachusetts high court, citing Kennedy's opinion, became the first to rule that gays had a right to marry.
If the court were to take up the case, Kennedy, 76, would likely control the opinion.
''If you care about history and your legacy, that must be pretty tempting, to write the court's opinion that could be the Brown v Board of Education of the gay rights movement,'' said Michael Klarman, a Harvard legal historian, referring to the case that ordered school desegregation. Still, the court's liberals also may hesitate. Justice Ruth Bader Ginsburg, though a leading women's rights legal advocate, has said she thought the court made a mistake in the 1970s by moving too fast to declare a national right to abortion.
If the court votes to hear the California case, it will be decided by late June. If the appeal is turned down, it means gay marriage will become law in California because of the appeal court's decision. The court may also put off a decision until the justices have decided on the constitutionality of the Defence of Marriage Act, also by June. The court is likely to announce whether it intends to hear the cases by Monday.
Many legal experts, including gay rights advocates, hope the justices will avoid a decision on the right to marry for now.
''The court is probably reluctant to impose same-sex marriage on the entire country right now. So, this is an excellent time for them to shut up and do nothing,'' said Andrew Koppelman, a law professor at Northwestern University in Chicago.
Two Los Angeles law professors - Scott Cummings at the University of California and Douglas NeJaime at the Loyola Law School - said the strong shift of public opinion in favour of gay marriage argues for the high court to stand aside for now. ''The tide is flowing only one way. So a wait-and-see approach seems prudent at this stage,'' Cummings said.
But in the south, the perspective may differ. ''Tennessee and the other deeply red states are not going to [allow gay marriage] on their own, at least for another 25 years,'' said Suzanna Sherry, a professor at Vanderbilt Law School. ''People here sincerely believe it will harm their marriage and offend God if gays are allowed to marry.''
She said the court had a duty to take up the issue. ''If there is no rational basis for denying gays the right to marry, the court should step in and protect gays from the tyranny of the majority,'' she said.
In contrast, the defenders of Proposition 8 argue the constitution ''leaves the definition of marriage in the hands of the people, to be resolved by the democratic process in each state''. Lawyers for Indiana and 14 other states also urged the court to reverse the appeal court's decision, which they called ''radical'' and ''insulting'' to the voters of California who sought to restore the ''state's traditional definition of marriage''.
Ted Olson, the conservative lawyer who joined David Boies to lead the legal attack on Proposition 8, acknowledges he is torn over whether the Supreme Court should hear the case.
''We won the case, and if they don't take it, our clients have won. They will be allowed to marry,'' Olson said.
''But if they take the case, it could lead to a broader victory. We believe gays and lesbians have a constitutional right to be treated equally. And if it is a constitutional right, you shouldn't have to try to win at the ballot box in every state.''
Los Angeles Times