Sometimes the significance of an item in the news can be measured by how little attention it attracts. To see how far the cause of gay rights has progressed in such a remarkably short period of time, consider the following sentence buried in an otherwise banal Associated Press report about Barack and Michelle Obama’s vacation plans over the recent Father’s Day Weekend in Rancho Mirage, California. “They are staying with White House decorator Michael Smith and his partner, U.S. Ambassador to Spain James Costos, at their vacation home.”

Not long ago, the notion of the First Couple spending a long weekend with a gay one, let alone advertising it to the press, would have presented the White House Chief of Staff with a PR headache. Would the public read too much into it? Would it signal support for same-sex marriage? How will it play in Peoria? Now, nobody bats an eye.

American presidents have long had gay friends and advisers, many of whom have occupied positions not so stereotypically swish as White House decorator. One could conceivably start the list with William King, who served as vice president to Franklin Pierce, and is speculated by some historians to have been the lover of President James Buchanan. More often than not, however, their homosexuality was a closely guarded secret, revealed unintentionally or as a result of embarrassing scandal. It is only very recently that the leader of the free world has felt secure enough to let it be known that he’s friends with friends of Dorothy...