Presidential powers don’t extend to pop culture.

We’re asking a lot of Barack Obama, just to right the sinking ship of American politics. Can we expect him to save American culture as well? Can a president spin that much gossamer from his oratory? Can the American people make better books, movies and music, inspired to new heights by better speeches and our better angels?

If history is any guide, the answer is simple: No, we can’t!

Presidents influence a lot of things -- interstate commerce, NASA weather balloons, which species make it onto the endangered list. But none of that has anything to do with culture. Indeed, a plausible case could be made that a president with a high approval rating has a positively baneful effect on the work of the imagination.

An industrious researcher might argue that a handful of presidents have introduced so much electricity into the atmosphere that a form of spontaneous cultural combustion followed. To a degree, that happened with John F. Kennedy, who audaciously declared that a new generation had taken over. Throughout the 1960s he was proved correct, often in ways of which he would have disapproved. It’s amusing to note that the Kennedys were often described as having long hair; it does not take too much imagination to link them to the Beatles and all that followed.

JFK probably had an even more direct impact on the New Journalism that revolutionized writing in the 1960s. Not only in his own way of speaking -- his sentences, punctuated by pugilistic jabs, were 10 times more dynamic than Eisenhower’s speeches -- but also in the way he carried himself as a postmodern celebrity, amused by all the attention.

This comes out in Theodore H. White’s book “The Making of the President: 1960" and in the flood of deconstructions that followed. In fact, the piece that may have kicked off New Journalism was about JFK -- Norman Mailer’s “Superman Comes to the Supermarket,” which appeared in Esquire in November 1960. It offers one of those fascinating glimpses of an old world ending and a new one beginning -- appropriately enough, in Los Angeles, where the phrase “New Frontier” was coined at the Democratic Convention.

Mailer, of course, is breathtakingly condescending about L. A. (“It is not that Los Angeles is altogether hideous, it is even by degrees pleasant, but for an Easterner there is never any salt in the wind; it is like Mexican cooking without chile, or Chinese egg rolls missing their mustard.”) But the piece has a nervous energy that percolated into so much of American culture in the 1960s -- a future glimpsed by Mailer in this weird sentence about JFK: “Yes, this candidate for all his record; his good, sound, conventional liberal record has a patina of that other life, the second American life, the long electric night with the fires of neon leading down the highway to the murmur of jazz.”

Kennedy’s cultural footprint was large in other ways. He had better state dinners than most; the one in May 1962 for French writer and diplomat André Malraux more or less achieved the Euro-sophistication that 200 years of American social climbing had grasped toward. (Henry James would not have believed it possible.) But even under JFK, “culture” was never easily defined, veering from Malraux and cellist Pablo Casals to Frank Sinatra and the Rat Pack. Or Ian Fleming, whose books Kennedy loved, and whose career he helped enormously by saying so.

Presidents do have a certain power to command culture into existence. To some extent, that’s what happened with the New Deal, when FDR ordered out-of-work writers, artists and actors to perform for the state, creating an enormous body of documentary work about the American people, still valuable seven decades later.

In addition, FDR’s conversational way of speaking may have opened up Americans: FDR “came through to people,” according to Arthur Schlesinger Jr., “because they felt -- correctly -- that he liked them and cared about them.”

And yet, when one considers the key cultural moments of the last century, it’s fairly clear that presidents were largely irrelevant. The Roaring ‘20s, for instance, were not made more so by Calvin Coolidge, who served as a hilariously deadpan maestro to the crazy orchestra playing all around him in the Jazz Age. Nor did Harry Truman, for all of his good qualities, inspire new forms of creativity in the late 1940s; no one would confuse his corny barrel-rolls with the bebop runs of a Thelonious Monk.

In fact, the more I think about it, the more it seems that real culture doesn’t need the support of the state. Rather, a fighting culture needs a worthy adversary. That’s why I’m convinced, after much careful consideration, that the greatest cultural president in U.S. history was California’s own Richard Milhous Nixon.

Yes, Nixon was, and is, the one. Trying to relate to a new generation, he invited the Carpenters (“young America at its best”) to play the White House in May 1973. Everything about him placed him in direct opposition to the culture boiling over at exactly that moment in our history. In other words, he was perfect.

Was there ever a funkier time than the Nixon era? Urban America never sounded so good. Hard rock was never harder; glam never glammer. American literature was scabrous and provocative. Hollywood reached a peak that it has never returned to.

So, while it’s fantastic that Obama is about to become our 44th president, let’s keep expectations realistic. For good old-fashioned American culture, with its endless capacity to surprise and subvert, we just might need a divider, not a uniter.

Widmer is the author, most recently, of “Ark of the Liberties: America and the World.” He was a speechwriter for President Clinton.