Whatever the Supreme Court decides, it seems same sex marriage is here to stay. As the cover of Time put it, “Gay Marriage Already Won. The Supreme Court Hasn’t Made Up Its Mind – But America Has.”

Even some social conservative rabble-rousers have conceded defeat. Fox News’s Bill O’Reilly, who in the past has compared gay unions to marrying a goat or a dolphin, has flipped, saying his views have “evolved.” “The compelling argument is on the side of homosexuals,” O’Reilly said last week. “The other side hasn’t been able to do anything but thump the Bible.” Rush Limbaugh, too, is reluctantly resigned to the change. “I don’t care what the Supreme Court does, this is now inevitable,” he said.

Few social liberals thought marriage equality would be as easy as this, but public support has been so swift that politicians of both stripes have rushed to endorse the legitimacy of same sex marriage. Even President Barack Obama and Bill and Hillary Clinton were left playing catch-up.

Until recently gay marriage was widely judged a step too far that might put at risk the central battle over LGBT equal rights. The settling of the issue is symptomatic of a broader demographic movement in which social attitudes about personal freedoms have been transformed by what social scientists call “cohort replacement” ‑ in which a less tolerant generation has been replaced over time by more broad-minded young people.

When the president chose to include in his second Inaugural Address an appeal for a more generous and kind society, even some of his supporters thought he was wasting his time. The nation, they said, was not ready to complete the social revolution that began in the 1960s. “Our journey is not complete,” Obama said, “until our wives, our mothers and daughters can earn a living equal to their efforts. Our journey is not complete until our gay brothers and sisters are treated like anyone else under the law.”