Tyler Cowen thinks it might be me:
Doesn’t Andrew Sullivan have a reasonably strong claim to that title, especially after the recent Supreme Court decisions on gay marriage? Sullivan was the dominant intellectual influence on this issue, from the late 1980s on, and that is from a time where other major civil liberties figures didn’t give gay marriage much of a second thought, one way or the other, or they wished to run away from the issue. Here is his classic 1989 New Republic essay. Here is a current map of where gay marriage is legal and very likely there is more to come.
Ross generously expands on Cowen’s argument:
I think the case of his work on gay marriage is distinctive. No doubt there would have been a major push for same-sex wedlock without Sullivan: Deep trends favored its adoption, other eloquent writers made the case, and other countries and cultures have taken different routes to a similar destination. But no writer of comparable gifts was on the issue earlier, pushed harder against what seemed at the time like an unassailable consensus, engaged as many critics (left and right, gay and straight) and addressed himself to as many audiences as Sullivan. No intellectual did as much to weave together the mix of arguments and intuitions that defines today’s emerging consensus on the issue — in which gay marriage is simultaneously an expression of bourgeois conservatism and the fulfillment of the 1960s’ liberative promise, the civil rights revolution of our time and a natural, Burkean outgrowth of the way that straights already live. And no intellectual that I can think of, writing on a fraught and controversial topic, has seen their once-crankish, outlandish-seeming idea become the conventional wisdom so quickly, and be instantantiated so rapidly in law and custom.
Again, it’s awfully hard to separate ideas from tectonic shifts in culture and economics, and I have enough of a determinist streak to doubt John Maynard Keynes’s famous maxim that “the power of vested interests is vastly exaggerated compared with the gradual encroachment of ideas.” But just as Keynes heard clear echoes of “academic scribblers” and “defunct economists” in the rhetoric of his era’s politicians, so I hear echoes of arguments that Andrew Sullivan, and often Andrew Sullivan alone, was making thirty years ago in almost every conversation and argument I’ve had about gay marriage in the last ten years. There’s no other issue and no other writer where the connection between things I read as a teenager and lines I hear today is as clear and direct and obvious. And if that isn’t evidence of distinctive, far-reaching influence then I don’t know what is.
What Sullivan did — and he wasn’t alone, but as Douthat says, he was there first, and most effectively — was build off the ground cleared by the Sexual Revolution — the bourgeoisification of what were, within living memory, outlaw sexual values — and claim it for the ultimate outlaws in the traditional Christian vision of sex and sexuality: gays and lesbians. What Sullivan and those he helped lead did was radical — and he achieved it by making a kind of conservative case for a revolution, by forcing what people in the post-Christian West already believed about sex, religion, and individual liberty to its natural conclusion. That’s something. That’s something huge.