The power and essence of yesterday's historic federal court ruling on gay marriage can be found on page 74 of the decision. Judge Vaughn Walker, in the midst of his meticulous declaration that California's gay marriage ban violated the U.S Constitution's equal-protection and due-process guarantees for all Americans, specifically said this:

"Individuals do not generally choose their sexual orientation. No credible evidence supports a finding that an individual may, through conscious decision, therapeutic intervention, or any other method, change his or her sexual orientation." The judge then backed up his conclusion by citing 12 factual examples drawn from the trial evidence - most notably, scientific and survey findings from a psychology expert, Gregory Herek; and, as the judge dryly noted in his ruling, the foes of gay marriage "did not present testimony to contradict Herek."

Given the fact that Walker's exhaustive ruling will probably wind its way to the U.S. Supreme Court, the passage on page 74 is critically important. The judge basically concluded, based on the scientific evidence presented at his trial, that gays deserve full equal-rights protection under the Constitution - just like any other underdog now recognized by the courts as an "identifiable class," such as minorities (who can't choose their skin color), and women (who can't choose their gender).

Courts have often denied gays the equal protection of laws guaranteed by the 14th Amendment because the gay "lifestyle" was deemed merely to be voluntary "conduct," an argument that was again floated in Walker's court earlier this year. He has now rejected that argument, on factual grounds. Federal appeals judges - and, ultimately, high-court swing voter Anthony Kennedy - may well be at pains to toss out the trial evidence and contend anew that gays deserve less status, and hence less constitutional protection, than others. (Indeed, Walker appeared to aim his ruling for Kennedy's ears, with frequent quotes from recent Kennedy-authored gay-friendly rulings.)

Moreover, what Walker concluded yesterday ("Moral disapproval alone is an improper basis on which to deny rights to gay men and lesbians") was no different than what Ted Olson - one of the pro-gay marriage lawyers in the case, and a veteran conservative Republican activist - stated in a magazine column back on Jan. 9: "Science has taught us, even if history has not, that gays and lesbians do not choose to be homosexual any more than the rest of us choose to be heterosexual. To a very large extent, these characteristics are immutable, like being left-handed."

The long-awaited federal ruling nixes Proposition 8, the '08 California ballot measure that banned gay marriage. Fifty-two percent of voting Californians had supported the ban, which is why, late yesterday, the enemies of gay marriage naturally contended that the ballot had been usurped by "the whim of one judge," that (in the words of the right-leaning Concerned Women for America), "Judge Vaughn Walker has chosen to side with political activism over the will of the people."

But that complaint is almost as boring and predictable as A-Rod's steroid-fueled trudge to 600 homers.

Federal judges are supposed to stick up for the Constitution, checking and balancing popular passions. That's why the Founders created that branch of government in the first place. If the 1954 Supreme Court had not stepped in to ban segregation in Brown vs. Board of Education, and had instead yielded at that time to "the will of the people" in Dixie, those Woolworth luncheonette counters, and other public accomodations, would have long remained whites-only.   

Indeed, Judge Walker, on page 130 of his decision, shredded the conservative complaint about so-called judicial tyranny in a single pithy sentence:

"That the majority of California voters supported Proposition 8 is irrelevant, as 'fundamental rights may not be submitted to a vote; they depend on the outcome of no elections.'"

Fundamental rights may not be submitted to a vote...The judge took that quote from a 1943 decision by the U.S. Supreme Court. If yesterday's federal ruling is ultimately reviewed by the Roberts brethren, perhaps a slim majority will respect judicial precedent - as well as the factual evidentiary record amassed at Walker's trial. Of course nobody would be shocked if they don't, but gays seeking to marry will eventually get their Brown ruling. The weight of the evidence, and of history itself, is on their side.