It’s headed to the highest court in the land. The U.S. Supreme Court agreed today to decide whether gays and lesbians can marry nationwide, resolving one of the country’s fiercest debates. In October, the justices declined to take up the issue, tacitly allowing gay marriage to expand from 19 to 36 states since then. A split among federal appellate courts is forcing the justices to act now. Their ruling, due out by June, will surely end up as one of the landmark cases of our time.