"If you say that marriage is a fundamental right, what state restrictions could ever exist?" Sotomayor asked before referencing polygamy and incest among adults.
Olson responded by saying that polygamy raises questions "about exploitation, abuse, patriarchy, issues with respect to taxes, inheritance, child custody it is an entirely different thing."
"If a state prohibits polygamy," he said, "it's prohibiting conduct. If it prohibits gay and lesbian citizens from getting married, it is prohibiting their exercise of a right based upon their status."
At one time, the Utah-based LDS Church practiced polygamy, which it renounced in 1890. The faith's leaders directed members to support Prop 8 in 2008 and signed on to a friend-of-the-court brief asking the Supreme Court to leave same-sex marriage to state legislatures and Congress.