In a 5–4 ruling, the U.S. Supreme Court today struck down the 1996 Defense of Marriage Act (DOMA). Writing for the majority, Justice Anthony Kennedy argued that DOMA wrote “inequality into the entire United States Code” and “made unequal a subset of state-sanctioned marriages.”

Did it? What is marriage anyway? Robert P. George, one of America’s most acclaimed and influential thinkers, addresses these crucial questions.