This article is a February 17 update of Paul Starr's earlier column 'Judicial Overreach'.

Even if Massachusetts legislators pass a constitutional amendment banning same-sex marriage when they reconvene on March 11, their initial failure to reach an agreement in February points to a more general impediment in the way of a constitutional amendment at the national level. But that impediment by no means ensures that such an amendment will fail.

In Massachusetts, according to The New York Times, the 199 members of the legislature have split three ways. About 40 support same-sex marriage, roughly 90 oppose same-sex marriage but approve of civil unions, and 60 to 70 conservatives reject both alternatives. Although the advocates of civil unions are still expected to prevail, they were initially unable to win enough support from either of the other sides to command a majority.

A similar division over civil unions among opponents of gay marriage is already evident in Congress. The amendment being proposed by conservatives reads: "Marriage in the United States shall consist only of the union of a man and a woman. Neither this Constitution nor the constitution of any State, nor state or federal law, shall be construed to require that marital status or the legal incidents thereof be conferred upon unmarried couples or groups."

The chief sponsor of the amendment, Republican Representative Marilyn Musgrave of Colorado, insists that it would not prevent states from authorizing civil unions. But some of the legal scholars involved in formulating the amendment say the contrary, and there is no mistaking that after defining marriage as exclusively heterosexual, the amendment says that state as well as federal law cannot confer the "legal incidents" of marriage upon unmarried couples.

As a result, the Musgrave amendment seems unlikely to win support from advocates of civil unions. But an amendment clearly permitting civil unions may be unable to win support from conservatives.

So are we safe from a constitutional amendment banning gay marriage? I don't think so. Here's a scenario for its adoption: This spring, before any amendment to the state constitution can be adopted, Massachusetts begins performing same-sex marriages. A couple then attempts to get another state to accept its Massachusetts marriage license as legally enforceable. The state refuses on the basis of the federal Defense of Marriage Act, and the case goes to the U.S. Supreme Court.

If the Supreme Court upholds the state's position, that would quiet demands for a constitutional amendment. But a decision overturning the Defense of Marriage Act under the full-faith-and-credit clause of the Constitution might well generate sufficient momentum for passage of an amendment, most likely one that accepted civil unions but banned same-sex marriages. In order to get any limitation on same-sex marriage, conservatives would be forced into concessions they're not yet prepared to make.

One of several problems with such a constitutional amendment is that it would freeze in place contemporary understandings for future generations at a time when attitudes toward same-sex relationships are continuing to evolve. The same public-opinion polls that show majorities opposed to same-sex marriage indicate that young people accept the idea. Most likely, once American society became comfortable with civil unions, objections to same-sex marriage would decline.

That, of course, is the process that conservatives are trying to block and that supporters of the Massachusetts court decision are hoping to short circuit. And as much as I respect the gay-rights supporters who want full and immediate recognition of same-sex marriage, I am concerned that short circuits can have explosive -- and counterproductive -- consequences.

As I've written, I don't think that supporters of gay rights ought to dwell on the distinction between civil unions and marriage if, as in Massachusetts, spouses in civil unions would have "all the same benefits, protections, rights and responsibilities" as spouses in a marriage. Civil unions would equalize what states have the power to equalize: legal rights. If rights are equalized, differences in administrative nomenclature are not likely to govern social symbolism. The law is full of obsolete terminology that has no social importance. Nothing would prevent gays from celebrating as marriages what the law calls civil unions.

The attempt to equate the legal distinction between civil unions and marriage to the "separate but equal"; provisions for public services overturned in Brown v. Board of Education is misleading in three respects. The "separation" in that case meant physical and social segregation; it involved separate allocations of resources; and when the Court declared segregation unconstitutional, it did so with the support of evidence regarding the actual effects of these arrangements. In ruling against civil unions, the Massachusetts court had no evidence of actual effects, and because the law would have explicitly established the same "benefits, protections, rights and responsibilities" in civil unions as in marriage, it is difficult to imagine that there will be effects of the kind that figured in Brown. The Massachusetts court should have refrained from ruling on a question on which it lacked evidence and, at least in the short term, deferred to the state's elected representatives.

There is such a thing as not knowing when you've won the game. Gays ought to recognize that with civil unions they have already won and that insisting on an immediate acceptance of the term "marriage" is to rub defeat in the faces of the traditionally minded.

Read a letter from Phineas Baxandall of the John F. Kennedy School of Government at Harvard University in response to this article.

Paul Starr is co-editor of the Prospect.

Paul Starr