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.”

They have friends on the Supreme Court. In arguments over a California ban on gay marriage, Justice Samuel Alito expressed reservations about abandoning time-honored arrangements. “Traditional marriage has been around for thousands of years,” he said, while same-sex marriage is “newer than cell phones or the Internet.”