The Defense of Marriage Act, the Clinton-era statute prohibiting federal recognition of same-sex marriage, isn't technically at issue in the high-profile battle over the fate of Proposition 8 in California. So the booming denouncement of the act's constitutionality last week by a venerable federal judge in Massachusetts can't and won't settle the challenge to Prop 8, the statewide voter initiative which has banned same-sex marriage in the Golden State. It will, however, almost certainly be quite influential.

In Boston, U.S. District Judge Joseph Tauro, a Nixon appointee, did not mince words in dispatching the portion of the federal marriage statute that prohibits lawfully married same-sex couples (in Massachusetts and elsewhere) from receiving certain federal benefits. The judge was brutal in his assessment of the legitimate "interest" the federal government could have in regulating marriage, which has traditionally been managed by state laws, and he vitiated many of the other legal arguments posed by opponents of same sex marriage everywhere, including in California in the Prop 8 trial. Most important, Judge Tauro declared:

"DOMA fails to pass constitutional muster even under the highly deferential rational basis test. As set forth in detail below, this court is convinced that 'there exists no fairly conceivable set of facts that could ground a rational relationship' between DOMA and a legitimate government objective. DOMA, therefore, violates core constitutional principles of equal protection."

Hundreds of thousands of pages of legal scholarship have been written over the decades about what Judge Tauro calls the "highly deferential rational basis test." I have deliberately chosen the Wikipedia entry as a guide because it's as good a brief description as any (and because I hate reading legal scholarship). Rational basis review, "tests whether a governmental action is a reasonable means to an end that may be legitimately pursued by the government. This test requires that the governmental action be 'rationally related' to a 'legitimate' government interest. Under this standard of review, the 'legitimate interest' does not have to be the government's actual interest. Rather, if the court can merely hypothesize a 'legitimate' interest served by the challenged action, it will withstand the rational basis review."

Judge Tauro struck down Section 3 of the Defense of Marriage Act even after giving it the most benefits of the most doubts allowed under Supreme Court precedent. This is no small thing in evaluating the weakness of the federal statute or the failings of the larger argument against same-sex marriage. And you can be sure that the federal judge in California presiding over the Prop 8 trial has taken careful notice of both the language and the tone of Judge Tauro's decision.

Indeed, in San Francisco last month, U.S. District Judge Vaughn Walker asked the plaintiffs in the decidedly one-sided Prop 8 trial: "Even if enforcement of Proposition 8 were enjoined, plaintiffs' marriages would not be recognized under federal law. Can the court find Proposition 8 to be unconstitutional without also considering the constitutionality of the federal Defense of Marriage Act?"

"Yes," the plaintiffs happily answered in written form: We "have challenged only Prop. 8 in this litigation. The Court need not -- and in the absence of a federal defendant, should not -- address the federal Defense of Marriage Act in this litigation. It may be that the Court's ruling will have implications for the Defense of Marriage Act and other similar laws that discriminate against gay men and lesbians. But such implications, if any, will depend on the parameters of this Court's decision."

Judge Walker also asked the parties about the application of the "rational basis" test. Of the plaintiffs, the folks challenging Prop 8 and supportive of same-sex marriage, Judge Walker asked this: "Assume the evidence shows Proposition 8 is not in fact rationally related to a legitimate state interest. Assume further the evidence shows voters genuinely but without evidence believed Proposition 8 was rationally related to a legitimate interest. Do the voters' honest beliefs in the absence of supporting evidence have any bearing on the constitutionality of Proposition 8?"

The response from David Boies and Ted Olson and Company was: "... the genuinely held beliefs of voters who enact an arbitrary, irrational, and discriminatory law cannot shield the measure from constitutional scrutiny. Voters' unfounded and discriminatory stereotypes are not a substitute for proof that a law actually furthers a legitimate state interest. Indeed, those who disfavor a particular group often genuinely believe and accept negative stereotypes about the disfavored group, even where such stereotypes are wholly unsubstantiated. The constitutionally relevant question for rational basis purposes is whether Prop. 8 in fact 'advance[s] a legitimate government interest'-- not whether the voters believed that it did."

Of the defendants, the folks supporting Prop 8 and who oppose same-sex marriage , Judge Walker asked: "Assuming a higher level of scrutiny applies to either plaintiffs' due process or equal protection claim, what evidence in the record shows that Proposition 8 is substantially related to an important government interest? Narrowly tailored to a compelling government interest? The answer, from this side, was: "Because Proposition 8 neither infringes a fundamental right nor discriminates on the basis of sex, and because gays and lesbians are not entitled to heightened protection under the Equal Protection Clause, Proposition 8 is subject only to rational basis review. Even if heightened scrutiny applied, however, Proposition 8 would readily satisfy such scrutiny."

Judge Tauro was willing to toss the federal marriage act even after applying the most lax constitutional test to it. Based upon his questions, it looks like Judge Walker is noodling these days over which constitutional standard to apply to his analysis of the legitimacy of Prop 8. If he takes the Tauro route, and I won't be shocked if he does, Prop 8 is doomed -- perhaps even before the United States Supreme Court.