ATLANTA -- The Georgia Supreme Court reinstated the state's constitutional ban on gay marriage today. In reversing a Superior Court judge's ruling, the high court ruled unanimously that the ban did not violate the state's single-subject rule for ballot measures when it was approved by 76 percent of Georgia voters two years ago. Neither the Supreme Court nor Superior Court Judge Constance Russell of Fulton County addressed the merits of gay marriage. Georgia already has a separate law on the books banning same-sex marriage in the state. Lawyers for the plaintiffs had argued that the ballot language was misleading because it asked voters to decide on both same-sex marriage and civil unions -- separate issues about which many people had different opinions. Governor Perdue had promised to call a special session of the Legislature next month if the court had not ruled by then.