Move over, William Buckley. Stand back, Gore Vidal. And run for cover, Uncle Sam: Paul Fussell, the nation's newest world-class curmudgeon, is taking aim at The American Experiment.

For the 58-year-old don, author and omni-pundit, that includes even the leafy collegiate charm of Princeton. "It used to be a great center of wit," says Fussell in mid-stroll, glowering at the placid streetscape, "but now it's subject to prole-drift." Prole drift? "Everything in the modern world drifts prole-ward all the time. Even the better classes have to wait in long lines, the quality of food degenerates, airline seating grows more cramped. In another 100 years, there will be no visible difference between the Soviet Union and the United States." But what about the enhanced comforts of the fabled Common Man? "Well," Fussell snorts, "his advantages are bought at my cost."

It's not easy to make Louis XIV look like Huey Long. But in terms of sheer industrial-strength affrontery, Fussell is just warming up. He also:

* Applauds the atom-bombing of Hiroshima, says those who don't are pathetically misinformed and admits that when he heard the news as a soldier in Europe, "we cried with relief and joy"; yet insists that whatever side you're on, modern war "is all mass-criminality";

* Claims "The Boy Scout Handbook" is "among the very few remaining popular repositories of something like classical ethics, deriving from Aristotle and Cicero";

* Condemns as irredeemably vulgar those who call "habitual drunkards people with alcohol problems, madness mental illness, drug use drug abuse . . . houses homes . . . and drinks beverages";

* Calls Ronald Reagan's position on school prayer "the most bizarre intellectual event since Martin van Buren"; and his supporters "Sunbelt imbeciles" who constitute "a public scandal";

* Believes "the vast expansion of public education" has created mass illiteracy by diluting standards, and deplores, in a recent issue of The New Republic, "the college swindle" whereby incompetent sod-belt schools, falsely promoted to universities by "the process of verbal inflation," have "set to work, with the best motives in the world, ripping off the proles";

* Damns Graham Greene for "inability to master English syntax," calls Herman Wouk's "War and Remembrance" "pure early 1950s Metro-Goldwyn-Mayer" and his career "a tragedy of vanity and publicity"; and then compounds the rebuke by warning that any author who writes a rebuttal letter to a review is "inviting the reader to regard him as an even greater ass and loser than before."

There are scores of such neo-Tory crankeries -- together with superbly lucid book reviews and affecting reflections on war -- in "The Boy Scout Handbook and Other Observations," his new collection of essays reprinted from Harper's, The New Republic and other polemical venues. And if the social satire seems infra dig for one of America's most esteemed intellectuals, Fussell is unconcerned: "When people say things that make me feel guilty about being frivolous, I remind them that I've paid my academic dues."

In fact, he has overpaid: He's a Harvard PhD, a chaired professor of English at Rutgers, and the author of four volumes of scholarly criticism. And that was before "The Great War and Modern Memory" (1975), his study of cultural myths and literary modes in World War I which won both the National Book Award and the National Book Critics Circle Award, and which Lionel Trilling called "one of the most deeply moving books I have read in a long time." A similar deluge of acclaim followed "Abroad: British Literary Traveling Between the Wars" (1980).

So for the last three years this Mencken manque' has been coming out of the ivy closet. "I like to get into things that people patronize," and "I'm extremely interested in folk rituals these days -- the rituals which help Americans to understand themselves." To this end, "I love going into lower-middle-class weddings, just wander in off the street and see what's going on." Some of his findings appear in a caustic little essay titled "Notes on Class" which he has just finished expanding into a book to be published by Summit next year. "It'll offend everybody," Fussell smirks.

He divides America into nine social classes -- three above and five below Middle -- and characterizes each by its taste in language, TV, body weight ("the flaunting of obesity is the Prole sign, as if the object were to give maximum aesthetic offense to the higher classes, and thus achieve a form of revenge"), clothing, food and housing. Through "facade study," he shows how house-front styles range from the classic Middle-Class picture window with a table lamp in the center ("the cellophane on the lampshade must be immaculate") to High-Prole ("religious shrines in the garden") to Mid-Prole ("plaster gnomes and flamingos") to Low-Prole (flower beds bordered by "defunct truck tires painted white"). He includes a sartorial analysis of the Reagan Cabinet ("Al Haig was superb--a master of Jacket-Collar Gape, indicating either a bad tailor or buying off the rack"), a disquisition on neck size ("it's an aristocratic feature -- people like Johnny Cash and Spiro Agnew have no necks at all") and concludes with a "Living-Room Scale" on which one can rate the status quotient of his own home. ("Any work of art depicting cowboys -- Subtract 3.")

His own small apartment in a building just succumbing to college-town Transient Funk he rates as "diminished Upper Middle." With its travel posters from the '30s and 18th-century drawings, hundreds of books in bookcases and stacked against the walls, the indolent tortoise cat named Dexter Margaret, it would seem to belong to a graduate student with a very small trust fund. Fussell sighs. "My income and assets were halved last May" when he separated from his wife, food writer Betty Fussell, and lost his $375,000 house, servant and two-car garage. Still, he gives himself a couple of bonus points for the bust of Augustus gravely surmounting the old refrigerator. And the visible TV, normally a liability, is redeemed by what he calls "parody display": Atop the tube is an ashtray in the shape of a toilet.

He starts work here at 6 every morning, setting a quota of half a dozen pages by noon, revising relentlessly. "Crappy work I do twice, good work I do three times." What's the bad stuff? "Oh, the things I do for The New York Times Book Review," to which he just mailed his piece on Tom Wolfe's new book. "Nobody takes it seriously. It's just designed to console a hangover on Sunday morning." And of his two contributing editorships, "I reserve my best work for The New Republic, because I respect the readers. Harper's, after all, is read by high-school teachers!"

There is some hypocrisy to this hauteur. Fussell will castigate other writers for unfounded generalizations, yet allows himself many a gibbering inanity, such as the assertion that the rich are "entirely devoid of intellectual or even emotional curiosity." He will ridicule an author for affected diction, yet is not immune to dictional bloat himself, persistently misusing "hypertrophied" when he simply means "large." And he will excoriate today's students for their neglect of Latin. But look at that Latin couplet on a 3-by-5 card pinned over his desk--isn't that a grammatical error in the second line? Fussell . . . uh . . . isn't sure.

But he's willing to admit that much of his indignation is a comic pose and his satire written "with due pathos." The class-system book is intended "to ridicule our obsession with status. The whole thing is supposed to be ironic -- it's an invitation for everyone to play." In fact, "my agent has proposed to Parker Brothers that they devise a game like Monopoly based on the book. You'd draw cards saying things like, 'Your son has just been admitted to Ohio Wesleyan -- Go back 3 spaces.' "

If that kind of dyspeptic snobbery sounds very British, Fussell replies, "I'm very British." He tries to spend one out of every four years in England. He named his daughter Rosalind after the character in "As You Like It"; and tried to name his son after Samuel Johnson. His wife complained, and the child was called Martin. But Fussell persisted in calling him Sam until the boy had his name legally changed. He even took up snuff recently, after a long tobacco career begun with cigarettes in the Army, pipes and cigars later. "But then I went to a doctor who looked up my nose and said, 'My God, what's going on in there!' " He gave Fussell 36 hours to quit or get nasal cancer. It's been six months and "I still sort of vibrate all over." And there is a sort of Anglican fussiness in his tendency to handle objects with the tips of his fingers, or the way he leaves a tip at lunch -- by fastidiously aligning all his pocket change in three parallel rows on the table top.

But he is very much an American author, pleased that "we can treat the language with a lot less respect than the British can. That's why there's no S.J. Perelman in England. I mean, over there it's the language of Shakespeare." He believes "the way to understand America is to study something else and then work by analogies"; thus "I learned to write by reading Johnson, Gibbon and Burke. They taught me the modern American sentence" which Fussell wields with elegant precision and deft syntactical lilt. Erudite but never stuffy.

Like his appearance. Most English professors, after a couple decades in the cloisters, come to resemble a cross between Peter Falk and the Poppin' Fresh Doughboy. Yet Fussell -- in snug jeans and open shirt, bare feet in leather deck shoes -- has the trim and craggy look of a rodeo star who's gone into money markets. He was born and raised in Pasadena, his father a prominent attorney, his mother "a clubwoman," his aim to be a journalist (he sold his first story and photos to Boys' Life) and his disenchantment growing. "I feel about California the way a Jew does about Munich," despising "the youth-worship, the empty-headed, beer-drinking anti-intellectualism." In junior college at 16 -- desperate to avoid the embarrassing nakedness of gym class because "I was fat and flabby, with feminine t--s and a big behind" -- he joined an ROTC unit.

It proved an ironically costly decision. At 20, called to World War II as a lieutenant, he found himself in France leading a unit of 40 into a slaughter. "I was sprayed with the contents of a soldier's torso when I was lying behind him . . . out of the holes in the back of his field jacket flew little clouds of tissue, blood and powdered cloth," he writes. "Near him, another man raised himself to fire, but the machine-gun caught him in the mouth, and as he fell he looked back at me with surprise, blood and teeth dribbling out onto the leaves." Finally Fussell himself was hit by fragments of an artillery shell which tore into his back and legs, leaving him with a 40 percent disability, a "dark, ironical, flip view of war," and an urge for "revenge." Even now he describes himself as "a pissed-off infantryman disguised as a literary and cultural commentator."

Returning to college, the first course he took was in Swift and Pope; continuing in 18th-century studies he found a psychic haven in complacent Augustan rationalism, grand satire and the "irony and nostalgia which all my work celebrates." Fussell defines irony as the emotion "occasioned by perceiving some great gulf, half-comic, half-tragic, between what one expects and what one finds." It is the subject of his most admired work, "The Great War and Modern Memory." For years he'd been reading World War I memoirs as a hobby, and when he was looking for a book topic, his wife said, "You're obsessed with the war -- why don't you write about that." The result was scholarly, copiously annotated yet emotionally stirring. "I felt as if it was being written for me. The real value of that book is the spirit of the men I served with. In writing it, I was just like a theatrical producer -- they were the actors."

The book surveys the post-Victorian metamorphosis from innocent belief in the progress and perfectability of man to the horror of the trenches and the ensuing spiritual dissonance and despair. Neither war nor literature would ever be the same, and he argues that "there seems to be one dominating form of modern understanding; that it is essentially ironic; and that it originates largely in the application of mind and memory to the events of the Great War."

The same ironic potential existed in World War II, he says, although "the modes of fear are different in every war. In the First, it was fear of loss of manhood, of appearing a coward -- a matter of national and personal honor. But by the Second, that was eliminated because we'd invented a thing called 'battle fatigue' -- a medical problem -- and instead people worried about getting dirt out of their wounds so they wouldn't lose their legs. The big fear was physical damage." Vietnam fiction, however, may not offer much. "Most war writing operates by telling people that it's much more horrible than they believe," but with Vietnam "irony is missing, and there is no disclosure, no surprise."

"The terrible thing," he says, "is that one can only write one book like 'The Great War,' a terribly serious one. I took all my emotions from the Second World War, disguised them, and put them into that book." Why not write directly about his war? It was partly a "degree of academic fear, since I didn't teach that period," and partly because he felt temperamentally closer to 1914, since "I had been a very civilized infantry officer" like the naive and poetry-soaked youths who marched to the Somme.

"One thing I was trying to do was establish a counter-current to the Yale School," the structuralists' creed "that criticism is supposed to be deeply mathematical, that it must imitate the physical sciences. I deplore that." He mourns the loss of "a whole class of general critics" like Malcolm Cowley and Edmund Wilson, humanists not too proud to deal with lowbrow subjects. So his analysis treats not only literary figures such as Wilfred Owen and Siegfried Sassoon, but diaries, newspaper headlines, pop songs, doggerel verse, recruiting posters and even gravestones; and it contains many powerfully written scenes of war action.

Melding literary criticism and popular history has been an academic anathema since the '50s. But "I know the characters in 'The Sun Also Rises' better than I know my friends--and that has always made it easy for me to write simultaneously about literature and life." And besides, he's naturally eclectic: "I'm positively neurotic about knowledge. I get up at 6 in the morning so I can read The New York Times before anybody else," and "I hate explaining things. It infuriates me that people can be so incurious about the rest of the world. Which is really what the book 'Abroad' is about -- that intense curiosity."

His widely admired 1980 study of English travel turns the same polydisciplinary apparatus on the confused interlude between the two wars in which the austere and Protestant British soul yearned southward toward the Catholic, boisterous, sun-baked beaches of the Mediterranean. The mass heliotropism displaced the old Wordsworthian ideal, "the traditional pastoral scene of quiet inland waters, wildflowers, sheep-filled meadows" and prompted the great age of English travel writing -- a genre which since 1940 has disappeared, he says, just as travel has degenerated into "tourism."

But "my war is virtually synonymous with my life," and he's now at work on an ambitious book about it, the structure of which will eventually emerge from the hundreds of file cards neatly arranged by author and topic heading, such as Blunders ("Did you know that one-third of the casualties in that war were caused by accidents?"), Alcohol, Transformations, Cowardice and Language. He works at a small, crowded desk by his bed, sitting in his old school chair with the Harvard crest on the backrest, typing on a massive Royal manual. At noon he stops for glass of white wine ("the drink of the upper middle class" because it implies that the virtuous bibbers have forgone their former "fashionable excesses," but that instead there are "an immense number of white-wine drunks") and "about 4 I get on the phone and arrange dates for the evening."

He wants to be remembered as promoting "the recognition that non-fiction prose is an art." All the esthetic cachet, he says, goes to other genres. "Look at the amount of status that lyric poetry persists in drawing to itself. It's dreadful, most of it, unreadable. And yet everybody just genuflects in front of it." He has no desire to write fiction -- "I can't take people seriously enough to care about the stories they might become involved in" -- and fears for the future of the essay, since it's "aimed at educated people, whereas an article is essentially for people who don't know anything and have to be told." Essayists, however, "add the new thing to a large tradition," which in his personal case includes Mencken, Twain, Waugh and "my model," George Orwell. "I'm archaic already. But as long as American snobbery needs the university as a framework for itself, my livelihood is perfectly secure."

"My main rule is, Thou shalt not be boring. I learned that teaching at a state university where the students are a little sleepy." After nearly 30 years at Rutgers, he finally decided to retire last year and devote himself full-time to writing. (He had almost quit during the know-nothing hippie spasm of the late '60s because "I felt that my contract had been abrogated. I had performed my job, but the university hadn't provided me with the students I was supposed to have.") His pension plan -- "the same one as the toll collectors on the New Jersey Turnpike" -- and assets would have made him independent. But then came the separation, and he appeared stuck when the University of Pennsylvania suddenly offered him their newly created Donald T. Regan chair in English Literature, endowed by the Treasury secretary's quondam colleagues at Merrill Lynch. Fussell will take the seat in 1984, after a year off to work on the World War II book, due at Oxford in 1988.

Meanwhile, there are the reviews, the essays, a forthcoming study of commencement ceremonies (in which tuition-bled parents are "recompensed by ritual") and a dozen other pressing projects. The thought pierces Fussell's inveterate sarcasm, and his voice grows grave. "I often feel that I was born to be destroyed in the war -- and that I should have been, like my friends and my sergeant. Yet I was miraculously spared. It's given me an almost mystical sense that I shouldn't waste time."