Meet Gore Vidal, political sharpshooter. "There is a lot to be said for being nouveau riche," he says, not quite spontaneously, "and the Reagan administration means to say it all. Of course, I myself am nouveau riche," he adds quickly, "and don't knock it until you've tried it."

Nouveau riche is a relative term. Vidal is a member of the wealthy and far-flung Auchincloss clan; he grew-up in the 1930s and '40s, on Merrywood, the Auchincloss estate in McLean, which also sheltered such of his semi-siblings as Jacqueline Kennedy Onasis and Princess Lee Radziwill. During the Kennedy administration, he was a frequent guest at the White House -- after all, he was related to the first lady in a complicated family structure whose ramifications run coast-to-coast and include such relatives as former senator Albert Gore.

"People wonder why I'm such a successful writer," Vidal says. "As I am related to most of the population of the United States, just to sell within the family is enough."

His mannerisms, honed to a fine edge at St. Albans, are as aristocratic as those of William F. Buckley, who is his precise opposite in politics and basic philosophy but a close match in the art of the arched eyebrow, the haughty tilt of a leonine head, the spoken word chosen as precisely as though he was writing it . . . and rewriting. If he has a worthy adversary, it must be Buckley -- or Hayakawa, the California senator he seems determined to replace; really determined, after past light flirtations with politics that have seen him allied with such figures as Benjamin Spock. When Vidal is assaulted by other writers, as he has been verbally by Truman Capote and physically by Norman Mailer (two episodes that have led to lawsuits), the cases seems not one of simple libel or assault but lese majesty.

Vidal fulfills the definition of a gentleman as one who does not cause pain -- unintentionally. At the moment he seems worried not about inflicting pain but about saying something in dubious taste. "Do you think it's all right to tell Reagan jokes so soon after the shooting?" he asks, leaning back in a comfortable armchair in his hotel suite.

Reassured that the president is once again healthy enough to be fair game, Vidal shifts back into the political mode:

"If he had any style, Ronald Reagan would announce he is going back to Santa Barbara, back to the ranch. He would say, 'I hate this town, I find it dangerous, and I'm sure George will enjoy it . . . George . . . what's his name? . . . George Bush.'"

Meet Gore Vidal, Hollywood personality (at the moment; other addresses include Rome and New York).

"There is a violent feeling against Ronald Reagan in the movie business, where I make my living. It's not sour grapes, but the people out there know actors. Reagan is an actor, and the one thing actors are paid for is to be plausible. There's nothing much in his head. There doesn't have to be; other people write the things for him to say. Actors are passive all their lives; they are moved around by directors like pieces of furniture. We probably should have elected Billy Wilder. He'd move the country around and we'd have some good jokes, and he's only 73 years old."

Vidal was in Washington recently to publicize his latest novel, "Creation" (which is now in its seventh week on the best-seller lists). The book has presented him with a new message that has him somewhat disturbed: "I believe I made a discovery while I was writing 'Creation.' I found that the human race is programmed like a DNA call. In my research, I found the same things happening simultaneously in four different places, four distinct cultures, in the fifth century B.C.: Greece, Persia, China and India. All these things were happening in these places: People were developing writing and logical systems of thought and new ethical orientations; they were revolting against a warrior caste that had taken power as invaders from the north; they were turning away from the sky gods who had dominated their cultures in the past. All at the same time, and without any significant communication among the different cultures.

"It's as though the human race were programmed for certain cultural developments to happen at a certain point, like an individual human baby: At a certain age, it waddles, then it stands up, begins to talk, reaches puberty and starts to reproduce. I had always thought of the human race as being sort of open-ended, since we evolved out of our friends, the monkeys. Now, I am starting to think of it as being more like a sort of very large virus, with a pre-established life span and strict limitations that are coded right into its basic structure. A virus can live just so long in a host, and then it dies. Is the end of the human race redetermined in just the same way? It has given me a horrible, almost a Calvinistic sense of predestination -- everything already determined. The period I studied was 2,400 years ago, and look what we have done since then. There are 4 billion of us now, with nuclear power and potentials that can hardly be guessed. I can't help wondering whether this includes the potential to destroy ourselves -- the certainty of destroying ourselves built into mankind from its origins."

That is about as much concentrated seriousness as Vidal can stand for the moment. If the human race is being pushed around, like the actors who should not be presidents, who is the director? Who wrote the script? "I don't know, of course," he says, "but it was probably a Greek god. They had the best sense of humor. Or perhaps it was the guy who dialogued with Job in the book of the same name. He had the answer to the problem of evil: I'm doing all this because I damned well want to."

Among other things, "Creation" is a rather detailed study of religious and philosophical ideas in the fifth century B.C. If it becomes a movie, some of the historic big names who appear in the text will present casting problems. Marlon Brando is a natural for Buddha, but how are you going to cast Socrates, who appears as a curious young man, Confucious, nearing the end of his life, Pythagoras, Darius, Xerxes, and above all the mysterious Zoroaster, who will have to be used in flashbacks?

After a study of many religious systems, which (with other background reading) took him six years, Vidal remains what he probably was when he began: a Confucian at heart. "I'm not much for sky gods," he says, "or heaven and hell or the survivial of the individual personality after death. I agree with Confucius that heaven is far and man is near and the proper organizing of society is all-important."

This may explain why he keeps getting into politics, and why he is continuing with his longstanding libel suit against Truman Capote, who once said in print that Vidal had been ejected from the Kennedy White House for disorderly behavior. Capote is now appealing the first decision in the case. "I'm not angry at Truman Capote," he says. "I feel rather sorry for him, and I wish that other people wouldn't keep urging him and allowing him to talk the way he does. In the libel suit, I was simply trying to establish the point that you should not tell lies about living people."

Is he speaking as a historical novelist, whose usual subject is dead people? Vidal smiles. "It shows at least that I draw the line."

Vidal originally became a historical novelist, he says, "because I couldn't believe that American history was as stupid and boring as I learned at St. Albans." At the moment (having written three movie scripts since he finished "Creation" somewhat over a year ago), he is engaged in a new historical project with Norman Lear; a study of Abraham Lincoln and his administration that already has about six hours' worth of material. From his description, it is not as dull as what he learned in school.

"Abraham Lincoln had syphilis," he says, "and presumably he gave it to Mary Todd Lincoln. I suspect that she died of paresis, and I'm trying to get a copy of her autopsy report. It was epidemic at the time, of course; practically the whole Union army had it. Lincoln told Herndon that he got it in 1837, and who knows whether it was ever cured. They had treatments at that time -- mercury and things like that -- but they were very uncertain and it is a treacherous disease. It can go into hiding for years and then erupt again. If Abraham Lincoln gave syphilis to his wife, it would certainly help to explain some of her character aberrations -- and also why he was so patient with her."