May 15, 2008, will go down in the history books as a great day in the march for equality.

For on that day, the California Supreme Court recognized the constitutional right of same-sex marriage.

It overturned hoary old arguments about “tradition,” which often is the flimsiest mask for prejudice.

It was 250 years of tradition that kept blacks as slaves.

It was another century of tradition that was invoked to oppose interracial marriage.

It was thousands of years of tradition and religion that reduced women to inferior status.

Just as it was tradition and religion that conspired to oppose gay marriage.

But as the state of Massachusetts has understood, and now as the California Supreme Court has made clear, there is no rational, secular argument for denying same-sex couples the right to marry.

There is a fundamental liberty issue at stake here, as well as a 14th amendment equal protection promise to redeem.

And the court in California has now redeemed it.

This decision puts the lie to the Democratic Party regulars who wished in 2004 that gay and lesbian couples would cool it, and that the mayor of San Francisco, Gavin Newsome, would back off from issuing marriage licenses.

I’m sure that are Democratic Party regulars who wish the California Supreme Court would have ruled the other way, too, fearing that this issue may not help the party in November.

But the equality train does not run according to the schedule of the Democratic Party. The activists have properly pushed their righteous case, and the California court has recognized its validity.

For gays and lesbians in California and around the country, this decision is cause for the greatest celebration.

As it is for all of us who cherish equality.