"To ... divide a class of married individuals into those with spouses of the same sex and those with spouses of the opposite sex is to create a distinction without meaning," Judge Joseph Tauro wrote in the case involving gay couples in Massachusetts, one of five states that issue marriage licenses to gays.

Unlike state legal battles in recent decades that have left a patchwork of state laws on same-sex marriage and civil unions, the cases in San Francisco and Boston test the U.S. Constitution and could lead to a national standard.

Yet the Supreme Court will likely move incrementally rather than sweepingly when cases arrive, Northwestern University law professor Andrew Koppelman says.

"The overwhelming majority of the states are still opposed to same-sex marriage," he notes. "The Supreme Court is reluctant to take on the whole country."

The outcome of any case could depend on Justice Anthony Kennedy, author of the major gay-rights rulings and the pivotal vote on the court.

No dispute directly testing gay rights was heard in the recently completed term, yet one case at the margins put Kennedy again in a decisive position. He was the key fifth vote to uphold a policy at a California state law school denying recognition to a Christian group that excluded gay student members. "A vibrant dialogue is not possible if students wall themselves off from opposing points of view," Kennedy wrote.

For Camilla Taylor, a lawyer in the Chicago office of Lambda Legal, a group that advocates for gay rights, it was a sign of Kennedy's "recognition that gay people are individuals who deserve respect."

Looking at recent legal action, including in Boston, Taylor adds, "There was a time when courts were not as receptive to our arguments. The tide has turned. While there still may be a few defeats here and there, I am convinced that we are watching history in the making."

Still, resolution of the cases now in lower U.S. courts and any Supreme Court determination on same-sex marriage is far from predictable.

"I'm still optimistic about the Supreme Court," says Maggie Gallagher, president of the National Organization for Marriage, which wants to preserve marriage for heterosexuals. Her group denounced Tauro's rulings against the Defense of Marriage Act and is awaiting a verdict from San Francisco.

"Many people do not understand that Proposition 8 is not just about California," Gallagher says. "This is a national case with national implications."

The Prop 8 debate

California voters approved Proposition 8 in November 2008 to reverse a state court ruling that May saying gay couples had a right to marry under the state constitution.

The challengers to that ban on same-sex marriage are represented by Theodore Olson and David Boies, adversaries in the 2000 presidential clash at the Supreme Court, Bush v. Gore. Olson argued on behalf of then-governor of Texas George W. Bush, and Boies, then-vice president Al Gore.

In closing arguments, Olson stressed the value of marriage to personal liberty. "The Supreme Court has said ... marriage is the most important relation in life," he said. Olson argued that when a state denies marriage to gay couples, it impinges on fundamental liberties.

Defending the ban on same-sex marriages in final arguments, Washington lawyer Charles Cooper cited society's interest in "procreative" relationships and children's welfare. When children are not raised by heterosexual couples, he said, "a host of ... very negative societal implications arise."

Judge Walker sounded skeptical of such arguments. Yet, he voiced concern about ruling broadly when only five states allow gay marriage. He suggested an untimely decision could cause a political backlash, as the high court did in 1973 when it made abortion legal nationwide.

The Boston decision

The question for Tauro in Boston was narrower: whether same-sex couples validly married in Massachusetts may be denied U.S. marriage-based benefits that heterosexual couples get.

Tauro said such denial of benefits violates the Constitution's equality guarantee. Tauro also ruled that the U.S. law intrudes on state authority.

He rejected the idea that the law advanced a federal interest in nurturing heterosexual marriage over homosexual relations. Tauro said he could see no way that denying benefits to same-sex spouses "might encourage homosexual people to marry members of the opposite sex."

END