Timing is everything in politics, no less true in US politics.
So this week's cases before the US Supreme Court over the future of same-sex marriage could not come at a better time for its advocates.
A poll just issued by the Washington Post and CBS News has 58 percent of Americans supporting gay marriage versus 36 percent opposed.
That is the mirror image of their positions just 10 years ago, when 55 percent were against it and only 37 percent in favour.
And among adults under the age of 29, 81 percent say they want gay and lesbian marriages to be recognised.
Moreover, two-thirds of all those surveyed want it to be held as a right under the federal constitution, not just legal on a state-by-state basis.
That is one of the questions the high court is being asked to settle.
Under the federal Defence of Marriage Act, signed by former president Bill Clinton, marriage is defined as a union of a man and woman only, and gay couples may not enjoy spousal benefits accorded to married heterosexual mates.
This is why New York resident Edith Windsor sued the government.
For more than 40 years, Edith and Thea Spyer had a romantic relationship, their marriage in Canada recognised as legal in New York before Thea died.
But Edith was judged liable for more than $300,000 in inheritance taxes, which she would not have owed if the couple had been man and woman.
And since the US constitution guarantees "equal protection" under the law, Edith is arguing for equal treatment.
Another case before the high court is the overturn of California's same-sex marriage law by the voters in 2008.
There too, gay-rights advocates argue that gay marriage must be protected as a constitutional right, regardless of what a legislature or popular referendum might choose.
Defenders of the status quo insist that the separate states should be the arbiters of gay marriage, not the Supreme Court.
That's the same argument rejected back in 1954, when the court ruled that racial segregation in public schools violated the US constitution, overriding racist laws in dozens of states.
That precedent was the crowbar that opened the door for the civil rights movement, and ultimately made it possible for the election of the country's first black president.
It was not until midway through last year's presidential campaign that Barack Obama, ever the careful and cautious politician, openly endorsed gay marriage.
He has been followed by Hillary Clinton, currently rated the country's most popular public figure, and the odds-on favourite to succeed Obama, if she opts to run for president in 2016.
Still, the laws in most states recognise only male-female marriages.
But if the Supreme Court sweeps them all away, it will uphold those who believe justice is not oblivious to the changing attitudes of the American public.