NASHVILLE (AP) - The Tennessee attorney general is asking the U.S. Supreme Court to let a ruling stand that upheld the state's ban on same-sex marriage.

The November decision by the 6th U.S. Circuit Court of Appeals marked a rare victory for gay marriage opponents. But because it conflicts with decisions in other circuits, legal observers believe it could push the Supreme Court to take up the issue of gay marriage, possibly as soon as this spring.

In a Monday court filing, Tennessee argues that there is no need for the Supreme Court to review the case because both the 6th Circuit's opinion and Supreme Court precedent recognize the inherent power of the states to define marriage. There is no conflict between the 6th Circuit and the Supreme Court, attorneys argue. As for the conflict between the circuits, the Supreme Court declines to hear cases all the time in which that is the case.

"The decision of the Sixth Circuit thus upholds and affirms Tennessee's 'historic and essential authority to define the marital relation,'" the brief reads, quoting from an earlier Supreme Court decision.

The 6th Circuit's 2-1 opinion affecting Tennessee, Kentucky, Michigan and Ohio said states have the right to set rules for marriage. And it said that changing a definition of marriage that dates to "the earliest days of human history" is better done through the political process, not the courts.

Shortly before the 6th Circuit's decision, the Supreme Court unexpectedly turned away an appeal from five states seeking to prohibit gay and lesbian unions. Plaintiff couples in the four states affected by the 6th Circuit's decision as well as defendant states of Kentucky, Michigan and Ohio have all asked the U.S. Supreme Court to decide the question once and for all. That makes Tennessee the only party to the decision to argue against a hearing by the high court.

The National Center for Lesbian Rights, which has hel ped the plaintiffs in the Tennessee case, issued a statement from senior staff attorney Christopher F. Stoll responding to Tennessee's Supreme Court brief. "We hope the Supreme Court will grant review and decide the case this term so that Tennessee and the other 14 remaining states can join the large majority of states that now allow same-sex couples to marry," the statement reads.