By agreeing to hear two cases that challenge legal limits on same-sex marriage, the U.S. Supreme Court is poised to decide whether gays and lesbians are entitled to fair treatment under the law. The issue is a timely one. A majority or near majority of Americans, depending on the poll, now say they support making it legal for same-sex couples to marry. Shifting attitudes are moving in one direction, toward broader acceptance. Approving marriage equality would affirm a civil right that will soon be a nonissue, much like interracial marriage is today, and put the court on the right side of history.The cases the high court has agreed to hear challenge the legality of California's Proposition 8, the ban on same-sex marriage passed by the state's voters in 2008, and the federal Defense of Marriage Act, a 1996 law that denies legally married same-sex couples the right to federal benefits afforded people in heterosexual marriages.In the California case, the ideologically riven court could turn the clock back on progress by resurrecting the ban passed by Proposition 8. It could do what fairness demands and recognize marriage equality in the Constitution for gays and lesbians. Or it could adopt a more narrow rationale articulated by the 9th U.S. Circuit Court of Appeals in San Francisco. That court found Proposition 8 unconstitutional because it imposed a legal disability on a disfavored class of people by repealing the marriage rights for same-sex couples that the California Supreme Court had recognized. This holding would have an immediate effect only in California.In 1996, the U.S. Supreme Court in Romer vs. Evans laid the groundwork for this narrower approach by setting aside a Colorado amendment that barred anti-discrimination laws protecting gays and lesbians. Justice Anthony Kennedy, the court's likely swing vote in the pending same-sex marriage cases, wrote for the court's majority, siding with the court's liberal members. His ruling overturned Colorado's amendment because it legally handicapped members of an unpopular minority. Kennedy also joined the liberal justices in 2003 in striking down a Texas sodomy law that targeted gays. Kennedy's rulings are a positive sign that he might once again demand the law not disadvantage gays and lesbians.The high court's second same-sex marriage case involves Edith Windsor, who legally married her lesbian partner in Canada in 2007. Due to the federal DOMA, when Windsor's partner died in 2009, Windsor was required to pay about $360,000 in federal estate taxes from which a heterosexual spouse would be exempt. This violates the Constitution's Equal Protection Clause, said the 2nd U.S. Circuit Court of Appeals. Other courts have drawn similar conclusions. With nine states and the District of Columbia now recognizing same-sex marriages, it is blatantly unfair that those couples cannot access the hundreds of federal benefits to which they should be entitled. The Obama administration is so certain DOMA is unconstitutional it is refusing to defend the law. That distasteful duty is being borne by the House Republican leadership.Some might argue that it is too soon for the high court to weigh in on one of the most divisive issues of the day. After all, when the high court decided in 1967 to sweep away anti-miscegenation laws, only 16 states still outlawed interracial marriage. At present 41 states, including Florida, do not allow same-sex marriage, while only nine states allow it. But this is an issue where evolving attitudes — like the support for marriage equality expressed by President Barack Obama earlier this year — are rapidly outpacing the laws on the books. Almost all groups of Americans have upped their support for marriage equality recently, with 73 percent of people between 18 and 29 years now approving, according to a Gallup poll last month. In November's general election, voters in Maine, Maryland and Washington state were the first to adopt same-sex marriage through popular vote. In Minnesota, voters turned aside a ballot measure to put its same-sex marriage ban into its Constitution.A tipping point has been reached. The time is right for the high court to banish this state-sponsored discrimination. The Supreme Court would not be leading as much as reflecting the emerging ethos of what constitutes justice.