WASHINGTON (AP) — A decision by a panel of federal judges to uphold anti-gay marriage laws in four states has created a split among the nation's appeals courts and made it very likely the Supreme Court will review the same-sex marriage issue.

But it is unclear whether the matter will reach the justices in time for a decision in June.

Lawyers for same-sex couples in Kentucky, Michigan, Ohio and Tennessee said they plan to ask the high court to reverse Thursday's 2-1 ruling from a panel of the 6th U.S. Circuit Court of Appeals in Cincinnati.

That court found that nothing in the Constitution gives same-sex couples a right to marry.

It was the first time an appellate court ruled in favor of state bans since a Supreme Court decision struck part of the federal anti-gay marriage law. Most courts have taken that decision to mean states cannot forbid same-sex unions.

The Supreme Court is under no obligation to the take the case, but Justice Ruth Bader Ginsburg recently said a split among the appellate courts would make her court's involvement likely.

Last month, before there was such a division, the justices turned away appeals from five states that sought to uphold their bans, even though same-sex plaintiffs who won in the lower courts also pressed the Supreme Court to intervene.

The effect of the Supreme Court's denial, and a subsequent appeals court ruling in the West, was to permit same-sex marriage or remove the legal underpinnings of state bans in nearly three dozen states.

Some essential things to know about the gay marriage movement and where it's headed:

WHEN DOES THE ISSUE RETURN TO THE SUPREME COURT?

The biggest question now appears to be one of timing.

If both sides can file their written arguments by late December, the justices should have enough time to schedule argument in the spring and decide the matter by late June.

The court usually fills its calendar for the term by mid-January, so if a same-sex marriage case is squeezed out, it would be pushed back into the term that begins next October. An argument in the fall of 2015, and a likely decision in the spring of 2016, could make gay marriage more of an issue in the 2016 presidential campaign.

Another issue for the justices is which case to take.

Federal judges in Kentucky and Michigan struck down each state's gay marriage ban. The cases from Ohio and Tennessee were more limited.

One other possibility is Idaho, which lost its case at the 9th U.S. Circuit Court of Appeals in San Francisco, and could appeal that ruling to the Supreme Court.

Idaho's attorney general, Lawrence Wasden, said the state intends to appeal, "but we don't have a firm timeline for when that will happen."

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HOW CAN AN APPEALS COURT RULE AGAINST SAME-SEX COUPLES AFTER FOUR APPEALS COURTS HAVE DECIDED IN FAVOR OF SAME-SEX MARRIAGE?

Federal appeals court have no obligation to fall in line with each other, and indeed, disagreement on important matters is a major factor in Supreme Court review.

The surprising thing has been how one court after another has lined up in support of gay marriage since the Supreme Court's June 2013 decision in Windsor v. U.S. But that decision itself divided the court 5 to 4, and while support for same-sex marriage has increased dramatically, there is still significant opposition.

Of course, Circuit Judge Jeffrey Sutton made clear in his ruling Thursday that what he thinks about same-sex marriage as a policy matter is beside the point.

Sutton wrote in his majority opinion that lower courts remain bound by a one-sentence decision dismissing a gay marriage case from Minnesota in 1972, even though other courts have said the decision no longer carries any force. He also disagreed with the other courts when he said judges should let the political process play out, not impose their will through judicial decree.

One last note on judges: All the judges who have voted to uphold anti-gay marriage laws are Republican appointees. Rulings striking down state bans have been made by Democratic and Republican appointees alike.

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WHAT IS THE STATUS OF GAY MARRIAGE CASES IN OTHER APPEALS COURTS?

The 5th U.S. Circuit Court of Appeals in New Orleans has scheduled argument in January in cases from Texas, where a judge struck down the state's ban, and Louisiana, where the ban was upheld.

Florida Attorney General Pam Bondi has asked the 11th U.S. Circuit Court of Appeals in Atlanta to review a judge's ruling that state law limiting marriage to a man and a woman is unconstitutional.

Cases also are making their way through courts in five states covered by the 8th U.S. Circuit Court of Appeals in St. Louis that do not permit same-sex couples to marry. A state judge and a federal judge in Missouri have ruled in favor of same-sex couples, but those rulings do not apply statewide.

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THE TALLY

Same-sex marriage is legal in 32 states, the District of Columbia and parts of Missouri.

Kansas, Montana and South Carolina are continuing their legal fight against same-sex marriage, despite rulings from federal appeals courts that oversee those states that concluded gay and lesbian couples have the right to marry.

Gay and lesbian couples may not marry in Alabama, Arkansas, Florida, Georgia, Kansas, Kentucky, Louisiana, Michigan, Mississippi, most of Missouri, Montana, Nebraska, North Dakota, Ohio, South Carolina, South Dakota, Tennessee and Texas.

The Supreme Court last year struck down part of the 1996 Defense of Marriage Act that forbade the federal government to grant tax, health and other benefits to legally married same-sex couples.