There was something broader going on, too, said Suzanne B. Goldberg, a law professor at Columbia.  “The court is talking about gay people, not homosexuals, and about people who have a social identity rather than a class of people who engage in particular sex acts,” Professor Goldberg said.  Lawyers for couples challenging California’s ban on same-sex marriage wasted no time in offering the judge hearing their case a translation of Justice Ginsburg’s sentence.  “The Supreme Court definitively held that sexual orientation is not merely behavioral, but rather, that gay and lesbian individuals are an identifiable class,” Theodore J. Boutrous Jr. wrote the next day to Chief Judge Vaughn R. Walker of the Federal District Court in San Francisco.  Charles J. Cooper, a lawyer for some of the defendants in the California case, said his opponents were reading far too much into the Supreme Court decision.  “The isolated, out-of-context statements quoted by plaintiffs suggest at most that discrimination based on homosexual conduct is, in certain contexts, a reasonable proxy for discrimination against gays and lesbians,” Mr. Cooper wrote to Judge Walker.  “But even assuming that this unremarkable proposition somehow points to a behavioral definition of homosexuality,” he went on, “it by no means follows that homosexual behavior is immutable.”  But if the plaintiffs’ reading is correct, Justice Ginsburg’s statement is both a time bomb and a tea leaf that will figure in litigations concerning same-sex marriage on two coasts. Judge Joseph L. Tauro of the Federal District Court in Boston issued two rulings on July 8 striking down part of the federal Defense of Marriage Act of 1996, and Judge Walker is expected to rule soon in the California case.  As the cases make their way to the Supreme Court, any signal from the justices is bound to be analyzed and scrutinized.  “Particularly in gay rights cases, the court has chosen its words with care over a long period of time,” Professor Goldberg said. “If read properly, this decision should have an impact all over gay rights jurisprudence both because of the specific rejection of the status-conduct distinction and the shift in tone.”  Judge Tauro, in considering the history of the federal law, noted that it seemed aimed at particular acts.  “Most people do not approve of homosexual conduct,” Representative Henry J. Hyde, the Republican chairman on the House Judiciary Committee said about the legislation in 1996. “They express their disapprobation through the law.”  The decision in which the statement appeared, Christian Legal Society v. Martinez, considered whether a public law school could deny recognition to a student group that excluded gay men and lesbians. The majority decided the case on narrow grounds that barely acknowledged the clash between anti-discrimination principles and religious freedom.  Barely, but not entirely. In her brisk aside, Justice Ginsburg put the muscle of a majority decision behind a proposition that had attracted only one vote when the court struck down a Texas law making gay sex a crime in 2003 in Lawrence v. Texas.  “Texas’s sodomy law is targeted at more than conduct,” Justice Sandra Day O’Connor wrote in a concurrence. “It is instead directed toward gay persons as a class.”  The Christian Legal Society decision was notable, too, because it was the only one in an argued case in the last term in which Justice Anthony M. Kennedy joined the court’s four more liberal members in a 5-to-4 decision. It is inconceivable that advocates for same-sex marriage can win in the current Supreme Court without his vote.  Some scholars cautioned against reading too much into very limited information culled from an inapposite decision.  “I don’t think it tips the court’s hand,” Michael C. Dorf, a law professor at Cornell, said of the Christian Legal Society decision. Professor Dorf filed a brief supporting the law school in the case.  William N. Eskridge Jr., a law professor at Yale, said, “The takeaway is that in the foreseeable future if you’re going to get five votes for anything remotely pro-gay it will have to be written very narrowly.”  Others were prepared to go a little further.  “The tone bodes well,” Professor Goldberg said of the decision. “The analysis bodes well. The great question is whether the tone and analysis will carry over when the court confronts marriage head-on.”  A version of this article appears in print on July 20, 2010, on Page A11 of the New York edition with the headline: Looking for Time Bombs and Tea Leaves on Gay Marriage. Order Reprints| Today's Paper|Subscribe
An aside about laws affecting gay men and lesbians in a recent case is being viewed as a potential signal for a future Supreme Court ruling on same-sex marriage.