When opponents of Proposition 8 sued in federal court last year to overturn the ban on gay marriage, some advocates of marriage equality thought it was a mistake. If they lost in court, their cause could be irrevocably damaged.

It turned out that the courtroom was an ideal forum to make the case that Proposition 8 denies same-sex couples the due process and equal protection rights guaranteed by the U.S. Constitution. A judge requires facts, not the kind of innuendo and fear-mongering that were used to sway voters during the Proposition 8 campaign. And there simply is no factual basis under U.S. law to argue that gays and lesbians don’t deserve the right to marry.

Years from now, when all Americans finally are permitted to marry whom they choose, we’ll look back on Wednesday’s ruling by Federal District Court Judge Vaughn Walker as a historic milestone — a moment when opponents of equality were exposed for their hypocrisy and the absurdity of their arguments.

Defenders of the 2008 initiative presented just two witnesses, both of whom Walker dismissed as unqualified in his decision. Not that it mattered. Neither could offer any credible evidence that gay marriage harms heterosexual marriage or that barring gays from marrying promotes any legitimate state interest.

The witnesses presented by the plaintiffs were, by contrast, a parade of distinguished academics, public officials and scientists. They made an airtight case that marriage, whether between same-sex or opposite-sex couples, promotes family stability. Married people are healthier, live longer and have more financial resources. The children of same-sex married couples see substantial benefits. Cities and the state would gain revenue if gays and lesbians were allowed to wed.

It wasn’t just poor courtroom maneuvering that led to this outcome. Says David Boies, a lead lawyer for the plaintiffs: “They didn’t fail because they’re bad lawyers; they failed because there isn’t any evidence to support the argument they’re advocating.”

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