Maine attorney Mary Bonauto, a pioneer in advancing gay rights, will be one of two lead attorneys arguing for gay marriage before the U.S. Supreme Court. Bonauto, who lives in Portland, was selected on Tuesday from a field of lawyers to represent gay couples in Ohio, Michigan, Kentucky and Tennessee on April 28, making the argument before the nation’s highest court to allow them to marry and have their marriages recognized in their home states. Bonauto, 53, will represent couples from Kentucky and Michigan who challenged their states’ same-sex marriage bans.