For gay marriage rights, look to Congress, not Supreme Court President Obama did the right thing last week by (finally) coming out in favor of marriage equality for all people. Gays and lesbians should have the same rights as heterosexuals to marry, and the president's explicit support should further that goal. But if the Supreme Court forces that change on the American people (through litigation over California's Proposition 8 or other cases), the probable backlash would be substantial and might well do more damage than good to the future of gay rights and other important causes. More than 30 states prohibit same-sex marriage through constitutional amendments and another 10 or so through legislation. No state has protected same-sex marriage by a vote of the people, and only a handful recognize it (by court decision or statute). By way of comparison, at the time the Supreme Court invalidated bans on interracial marriage in 1967, 16 states prohibited whites and blacks from marrying, and there were few organized political movements devoted to defending the racism behind the anti-miscegenation laws. Now, with the president's support, those in favor of same-sex marriage should begin what will be a long but necessary process of persuading Congress (not the Supreme Court) to take action on this issue. Two landmark cases, Brown vs. Board of Education and Roe vs. Wade, teach valuable lessons about the respective abilities of Congress and the Supreme Court to effect change on highly charged moral issues. In 1954, in Brown, the high court held that segregated schools violated the 14th Amendment. Although this decision was undoubtedly correct, nine years later, in 12 Southern states there were still virtually no desegregated schools. These states simply wouldn't comply, and the Supreme Court didn't have the will or the power to make them. Then, in 1964, Congress enacted the Civil Rights Act and conditioned federal money on a state ending its formal segregation. Almost immediately, white and black children began attending schools together at much higher rates. It was Congress, not the court, that fostered real change. In 1973, the Supreme Court decided in Roe that abortion was a fundamental right protected by the 14th Amendment, and it overturned most state laws on the issue. Less than a decade later, the Moral Majority and the Christian right had become major forces in American politics. Led by Jerry Falwell, Pat Robertson and others, this broad coalition was made up of conservatives espousing "family values," and opposition to busing, affirmative action and, of course, abortion, even when the woman's life was at stake. Although Roe certainly wasn't the only catalyst for the success of this movement, there can be little doubt the court's decision and the backlash against it played a prominent role. Moreover, inside the legal academy, Roe helped fuel the start of the Federalist Society which began its rise to prominence by opposing the "living Constitution" - the concept that contemporary conditions must be considered in interpreting the document's vague phrases - and arguing forcefully that Roe was a judicial activist decision embraced by liberal elites forcing unwanted change on millions of Americans. Roe has also negatively infected the judicial nomination process to this day, and made it much more difficult for liberal judges to be confirmed to the federal bench. I am a strong supporter of abortion rights, and if a woman's right to choose had been truly secured by Roe, maybe the backlash would have been worth it. But poor women today still have a difficult time obtaining abortions, and burdensome regulations on abortion are proliferating every year. A direct fallout of Roe was the withdrawal of almost all public money for abortions at the state and federal levels. There are virtually no abortion clinics in some states and many rural areas. And we are potentially only one vote away (JusticeAnthony M. Kennedy) from the explicit reversal of Roe. The right to abortion today, almost 40 years after Roe, is in no sense stable. The long-term lessons of Brown and Roe should be heeded by people in favor of marriage equality. Throughout its history, the Supreme Court has been able to stop progressive change (civil rights legislation in the 19th century, child labor laws in the early 20th century and recently campaign finance reform), but the court has rarely, if ever, been able to effectively cause progressive change. Rather than try to force this issue through the courts, we should start placing enormous pressure on Congress to repeal the 1996 Defense of Marriage Act, give same-sex couples equal rights under federal law and condition federal money for welfare programs on states recognizing same-sex marriage. Although this sounds implausible today, it is no less crazy than thinking in 1958 that six years later Congress would pass a law pressuring states to end segregation in public schools and barring discrimination in hotels and restaurants. People as talented as Ted Olson and David Boies (the lawyers who are working to overturn California's Proposition 8) should use their formidable talents to instead lobby and pressure Congress to bring about this change. If the Supreme Court does it by constitutional fiat, watch for a movement arguing for a federal constitutional amendment prohibiting same-sex marriage. Such a movement will probably be unsuccessful but would trigger fundraising and electoral opportunities for conservatives that could cause serious damage. On Friday, Supreme Court commentator Dahlia Lithwick (along with law professor Sonja West) argued persuasively that same-sex marriage should be a federal constitutional right. But that doesn't mean the time is right for the Supreme Court to impose that right on more than 40 reluctant states. As hard as it is for some people to accept, millions of Americans do not believe in marriage equality. A Supreme Court decision forcing them to accept it would only have the opposite effect and cause more intractability. It ignores the lessons of the past to think a court decision could guarantee equal rights for gays and lesbians. Just ask the thousands of women who face serious obstacles to obtaining safe and affordable abortions. Eric J. Segall, a law professor at Georgia State University, is the author of "Supreme Myths: Why the Supreme Court Is Not a Court and Its Justices Are Not Judges." Twitter: @espinsegall