Essential facts about Supreme Court gay marriage case

(Reuters) - The Supreme Court on Tuesday is set to hears arguments over whether states may ban gay marriage. Here is a look at the case, known as Obergefell v. Hodges. WHEN The arguments are set for Tuesday at 10 a.m. (1400 GMT). The session is scheduled for 2-1/2 hours. The court will provide a transcript of arguments and audio on its website (www.supremecourt.gov) that afternoon. LEGAL QUESTIONS The questions before the nine justices are: whether the U.S. Constitution's guarantees of due process and equal protection under the law cover a right to same-sex marriage; and, if they do not, whether states that ban same-sex marriages must recognize those performed elsewhere, based on the constitutional principle that states must respect the acts of other states. SIGNIFICANCE After more than two decades of litigation, a decision could determine whether gay men and women have a nationwide right to marry. Currently 37 of the 50 U.S. states and Washington, D.C. allow same-sex marriage. PARTIES The petitioners are gay couples seeking to marry or to have their marriages from other states recognized. The cases arose in Ohio, Michigan, Tennessee and Kentucky. The lead petitioner is James Obergefell, who wanted his home state of Ohio, which bans gay marriage, to recognize his Maryland marriage to John Arthur as Arthur was dying from amyotrophic lateral sclerosis, also known as Lou Gehrig’s disease. Obergefell sought to have his name on Arthur’s death certificate as surviving spouse. Richard Hodges is director of the Ohio Department of Health. LOWER COURT RULING The Cincinnati-based U.S. Circuit Court of Appeals for the 6th Circuit said lower courts were bound by a 1972 Supreme Court decision, Baker v. Nelson, that rejected a same-sex couple’s marriage claim. The 6th Circuit said any societal change on marriage rights would better come from legislatures and the political process rather than the courts. All the other regional federal appeals courts with recent decisions on the matter have ruled the opposite way and struck down bans on gay marriage. ARGUING FOR THE GAY COUPLES Mary Bonauto, of the Gay and Lesbian Advocates & Defenders, and Douglas Hallward-Driemeier, a former assistant U.S. solicitor general now in private practice. ARGUING FOR THE OBAMA ADMINISTRATION U.S. Solicitor General Donald Verrilli. ARGUING FOR THE STATES John Bursch, a former Michigan solicitor general, and Joseph Whalen, a Tennessee associate solicitor general. SUPREME COURT LINE-UP The nine justices have divided narrowly on gay rights dilemmas. In the most recent case, U.S. v. Windsor in 2013, the justices split 5-4 as they rejected a law defining marriage as between only a man and woman for purposes of federal benefits. Justice Anthony Kennedy, who is in the conservative camp but has taken the lead on gay rights, voted with the four liberals and wrote the opinion for the court. Joining him were Justices Ruth Bader Ginsburg, Stephen Breyer, Sonia Sotomayor and Elena Kagan. In dissent were Chief Justice John Roberts and Justices Antonin Scalia, Clarence Thomas and Samuel Alito. RULING A decision is expected by late June. (Compiled by Joan Biskupic; Editing by Will Dunham)