Like the sophisticated defenders of Proposition 8, DOMA's proponents are making a strong argument -- but one that may belong in a different case.

My colleague Andrew Cohen recently analyzed the brief filed in the Supreme Court by the proponents of California's Proposition 8, correctly noting that it makes by far the most coherent argument yet in favor of the referendum that rewrote the California Constitution to ban same-sex marriage. Proponents of the Defense of Marriage Act have also just filed their brief in United States v. Windsor, the companion case to the Prop 8 matter. (The coalition of House members who have taken on defending DOMA is known by the regrettable acronym BLAG -- the Bipartisan Legal Advisory Group.)

It's hardly surprising that the brief is first-rate -- BLAG is represented by Paul Clement, the most talented Supreme Court litigator of his generation. Its most powerful argument is this: Gays and lesbians are winning politically. The court should butt out and leave the decision about allowing same-sex marriage to the democratic process.

Ian Millhiser of the Center for American Progress tackled this argument in a recent post. He compares it to a Southern lawyer in 1967 arguing that African Americans were equal because they had held well-attended marches. I'm someone whose rabid partisanship on this issue can't be seriously doubted; nonetheless, I think the argument is more powerful than that. Gay rights and gay politics have had a pretty good four years. As the brief argues:

More than twenty years ago, the Seventh and Ninth Circuits recognized that "homosexuals ... are not without growing political power," and that "[a] political approach is open to them" to pursue their objectives. Whatever the limits of that conclusion two decades ago, there can be no serious doubt that the political power of gays and lesbians has increased exponentially since then.

Today, same-sex marriage is supported by President Obama (who has called for DOMA's repeal), Vice President Biden (who voted for DOMA as a Senator in 1996 but has since changed his view), and the Senate majority leader, the House minority leader, and the Democratic Party's 2012 platform. One-third of the members of the U.S. House of Representatives filed a brief in the court below attacking both the wisdom and constitutionality of DOMA. Polling indicates that by 2011, the proportion of Americans supporting same-sex marriage had increased from 27% to 53% in a span of only 16 years. The November 2012 elections witnessed "a record number of openly gay candidates" for Congress, and the election of the first openly gay U.S. senator.

In that same election cycle, voters in Maine, Maryland, and Washington state passed measures allowing same-sex marriage, and Minnesota voters defeated a proposed traditional marriage amendment to the state constitution. The Maine result demonstrates the capacity for the give and take of the political process to change voters' minds, as the Maine referendum effectively reversed the result of a 2009 referendum. In all, nine states and the District of Columbia now permit same-sex marriage. [I've omitted the legal citations in the above, thus rendering it into English.]

The question matters because one of the issues in Windsor is whether the courts should give special "scrutiny" to laws that disadvantage gays. This "level of scrutiny" issue is the heart of jurisprudence under the Equal Protection Clause. Laws that disadvantage racial minorities are looked at more skeptically than laws that harm, say, people over 65. That's because race discrimination thrives by locking minorities out of political power -- denying them the vote, for example -- while old folk have both the ballot and leisure to use it. So if gays really are playing on an equal footing in politics now, it's not irrational to ask the courts to let them work out their goals in legislatures and at the polls.

The brief concludes that "[i]n short, gays and lesbians are one of the most influential, best-connected, best-funded, and best-organized interest groups in modern politics, and have attained more legislative victories, political power, and popular favor in less time than virtually any other group in American history." That's perhaps a bridge too far. The current victories are hard-won, and that there have been stinging defeats as well.

In addition, there is a subterranean school of thought that views gays as too powerful, in need of a brisk reining-in. That perception echoes in Justice Antonin Scalia's dissent in Romer v. Evans. Romer overturned a Colorado state constitutional amendment; the amendment, passed by initiative, voided all local civil-rights laws protecting gays. Justice Scalia explained that the amendment was needed because gays had ways of amassing too much power at the local level:

The problem (a problem, that is, for those who wish to retain social disapprobation of homosexuality) is that, because those who engage in homosexual conduct tend to reside in disproportionate numbers in certain communities, have high disposable income, and of course care about homosexual-rights issues much more ardently than the public at large, they possess political power much greater than their numbers, both locally and statewide. Quite understandably, they devote this political power to achieving not merely a grudging social toleration, but full social acceptance, of homosexuality.

In the eyes of its enemies (and who seriously doubts Justice Scalia's distaste for homosexuality?), any persecuted minority may suddenly morph into a tyrannical over-caste, without pausing at the civic equality stop.

One would expect this argument to be made in the Proposition 8 case: If gays and lesbians lost a referendum in 2008, they may win one in 2014. But the Prop 8 defenders at best hint about this prospect -- perhaps because they feel it would concede more legitimacy to same-sex marriage than they would like.

DOMA, on the other hand, does not simply allow politics to work; it uses federal power to override, at the federal level, a state's sovereign decision to marry two adults. Many of the Supreme Court's conservatives -- particularly Justice Anthony Kennedy, the probable swing vote in the gay marriage cases -- show a great deal of solicitude for the dignity of states against the feds. DOMA disrespects state choices. The question is whether that federalism principle matters in a case as fraught as this one.