The American flag never comes down at 395 Concord Ave. in Belmont. Illuminated at night and resilient through foul weather, the Stars and Stripes provides the only glint of color near the bleak rectangle of red bricks. This is a decidedly no-nonsense building, surrounded by an equally no-nonsense post office and public library. No doubt about it, there is work to be done at the national headquarters of the John Birch Society, 12 minutes from Harvard Square.

Few topics prompt more immediate-and impassioned-responses than the John Birch Society. Reactionary. Ultra-right wing. Anti fluoridation. But almost no one seems to know how these associations came to exist. The answer goes back to a single book, a single angry man and his cause.

*****

In 1957, Robert Welch was fed up. He had enjoyed a successful 25-year career as an executive at the James O.Welch Company (his brother founded the Cambridge candy-making firm), but that couldn't contain the concern that was gnawing at him: Communism.

Welch decided to do something about it.

He wrote a book-later he said it was only an "unfinished manuscript," the contents of which were leaked by unscrupulous reporters-that began to explain the subversive and destructive forces at work in his country. The thesis of the "manuscript" The Politician, now in its ninth printing with more than 285,000 copies in print, is startling: "Dwight D. Eisenhower was, through his whole career, a dedicated, conscious agent of the Communist conspiracy," and was guilty of treason.

Twenty-three years later, Welch says in a prologue that "Obvious pressures to smother and ignore The Politician since its official publication are unmatched in the history of the book world." That statement's glaring hyperbole runs through the next 287 pages. The book contains no apparent factual errors, only mind-boggling leaps of imagination, including only evidence that suits his conclusion. Not surprisingly in a 1957 atmosphere still charged with the remnants of McCarthyism, the book caused a considerable stir.

Welch decide he needed a long-term outlet for his views, so on December 9, 1959, in Indianapolis, Ind., Welch and 11 friends founded the John Birch Society. John Birch was a young Baptist preacher who had served as an Army captain in China during World War II. Chinese Communists had killed him ten days after the Japanese surrendered, and Birch was, according to Welch, "the first American to die in World War III." The society's basic philosophy holds that "The world is engaged in this war from which either Communism or Christian-style civilization must emerge with one completely triumphant and the other completely destroyed."

*****

Of all the right-wing organizations in the United States-the Liberty Lobby, the Rev. Carl McIntire's Twentieth Century Reformation Hour, the Rev. Billy James Hargis's Manion Forum-Welch managed to build the only one with a broad base of popular support. The John Birch Society quickly jumped to about 50,000 members, and John F. McManus, director of public relations, says membership since then has remained between 50,000 and 100,000.

The secret to the society's longevity lies in the simplicity of its message and its diligence in spreading the word. Communists, or their minions, are working to see the "Christian style civilization" buried under Marx's big boot. But Birch Communism has almost nothing to do with Marx; "Communist" for the society is simply an adjective, a pejorative applied to any form of government control. John Birchers have a nearly pathological fear of government control; the line blurrs between traffic lights and the abolition of private property, both forms of governmental intrusion into people's lives. It is nostalgia tempered with paranoia. Publications like "The Glorification of M. L. King-A Victory for World Communism," show their confusion between real Communism, and any threat to the society's world inside 395 Concord Ave.. a place Peter Schrag called "hermetic reality."

The John Birch Society owns three building sin Belmont, two of them devoted entirely to the Birch publishing empire. In addition to a monthly Birch Society Bulletin, which 80-years-old Welch still writes, and a weekly reactionary news analysis magazine called The Review of the News, the society publishes hundreds of pamphlets like "McCarthy: The Truth, the Smear and the Lesson." and "They killed the President : Lee Harvey Oswald Wasn't Alone," (Surprise, he had help from Communists). The society also runs Western Island Press, publishers of conservative tracts like "Teddy Bare: The Last of the Kennedy Clan," an attack on the Senator's performance at Chappaquiddick. To complete the distribution system, the society sells its books and magazines at about 350 American Opinion bookstores, many of them in southern California. "We do our own publicity," McManus says. "That boils them in oil."

"Them," "They" are the Opposition, those dedicated to the end of "Christian-style civilization." Society publications usually call them "the Insiders," a form of shorthand. No one ever clarifies, however, who "they" are. Several recent publications offered the following villains: Jimmy Carter, homosexuals, the Trilateral Commission, the CIA, the big oil companies, the Democratic Party, the Ford Foundation, the Council on Foreign Relations, and most of all, the United Nations. The society itself. McManus points to a huge stack and says these are among the eight million petitions he has ready for distribution with the aim of removing the United States from that world body.

The early and mid-'60s saw the society's heyday; Life,, in its "Washington Report," said the society was engaged in "a massive shift from a semi-clandestine political guerilla force to a quasi-respectable pressure group," devoted mostly to withdrawal from the U.N., exposure of the civil rights "fraud," and the impeachment of Chief Justice Earl Warren. Then Attorney General Robert F. Kennedy '48 placed the group "in the area of being humorous." But Sen. Barry Goldwater (RAriz.), in a comment that would haunt him in his presidential bid, said, "I am impressed by the people in it."

However, Republicans fought the society from the start. Former vice president and future unsuccessful California gubernatorial candidate Richard M. Nixon said on the Jack Parr Show in February 1962, that politicians "who accept or seek support of organizations like the John Birch Society are not serving America." William F. Buckley Jr., in the National Review, revealed Welch's isolation in the conservative movement, calling The Politician " paranoid and unpatriotic drivel."