What do you call a person who loathed -- and was loathed by -- William F. Buckley Jr.; who despised the Judeo-Christian tradition as well as monotheism; who believed 9/11 was a setup; who wrote regularly for -- and was warmly received by -- the New York Review of Books, The Nation, and other left-wing flagship publications; who endorsed Dennis Kucinich for president; who ran for Congress from New York as a Democrat with the endorsement of Paul Newman and Eleanor Roosevelt and, later, ran for the Senate, also as a Democrat, from California; who criticized the Democratic party from the left throughout the Vietnam War and beyond; who described himself as an "anti-anti-Communist" at the height of the Cold War; and who, upon his death, was eulogized warmly by nearly the entire liberal and leftist establishments, here and abroad, as a national treasure?

Why, a conservative, of course.

So argues David Greenberg, the in-house historian at Slate magazine.

Greenberg's argument is a classic example of getting any number of trees right, but, after adding them all up, seeing -- instead of a forest -- some otherworldly landscape devoid of arboreal contours of any kind. His case comes in two parts. The first is that Vidal once said he considered himself a conservative. The second is that Vidal was an ass in the grand progressive tradition.

Greenberg -- rightly -- traces Vidal's intellectual roots back to a time when many progressives saw no difficulty in being elitists, racists, and opponents of mass society in every regard. Greenberg -- again rightly -- also notes that Vidal was a creature of great privilege, which helps explain Vidal's overweening sense of entitlement and resentment at a world that didn't defer to him as the hedonistic poet-prefect of ancient Rome he believed himself to be. "Vidal," writes Greenberg, "was a paradigmatic, almost stereotypical representative of the traditional American elite -- WASP lineage, prep schools, money, connections. Fashioning himself a latter-day Henry Adams, a valiant upholder of a civilization under siege . . . "

One might quibble that the author of the first major American novel celebrating homosexuality, who believed that "the great unmentionable evil at the center of our culture is monotheism," might not exactly deserve the label of paradigmatic, "almost stereotypical," representative of the traditional American WASP elite (that is one Herculean "almost"), or that a man who became known as the "sage of Ravello" -- that's Ravello, Italy, not Ravello, Ind. -- might not be overly inspired by American isolationism. But whatever, as the kids say.

Greenberg quotes the brilliant but problematic historian Richard Hofstadter, who wrote that the two branches of progressivism split in two. One branch, the good guys, went on to create New Deal liberalism. The other bloc went cranky and nativist. "Somewhere along the way a large part of the Populist-Progressive tradition has turned sour, become illiberal and ill-tempered," wrote Hofstadter. That, too, is true enough (or true enough for the space available here). But it's another thing altogether to say it became conservative. It became nationalistic, to be sure, but it also became radically leftist in almost every objective measure. Gerald Nye and Hiram Johnson (whom Greenberg names) didn't stop being progressives because of their isolationism or nativism, anymore than Father Coughlin stopped being a leftist after he broke with FDR.

What is fascinating -- though not surprising -- is that a liberal like Greenberg can see that Vidal was a crank and fraud in so many regards, but he's perfectly willing to take Vidal at his word when he called himself "conservative." Odder still is that, while Greenberg acknowledges that Vidal was a "bigot," crank, and fool for nearly his whole life, he seems utterly uncurious about the fact that the Left loved him as one of its own and the Right saw him for what he was.