In the battle over same-sex marriage, opponents are strongly in favor of deferring to the wisdom of our ancestors. Indiana Gov. Mike Pence uses the prevailing formula when he says, "I support traditional marriage." The Christian Coalition of America urges its friends to "Say 'I Do' to Traditional Marriage." But invoking age-old customs has not served to convince the American people, most of whom now favor letting gays wed. As Steve Chapman writes, Americans have rarely rallied to the idea that we should do something just because that's what was done in the time of Henry VII or even George Washington.