Just 10 minutes from Harvard Square, the country's largest liberal playground, stands the headquarters of the John Birch Society, the arch-conservative group which believes a "global conspiracy" today threatens society with worldwide communism.

"If you want to know the truth, that's why we're so controversial," says the Society's public relations director, John F. McManus, in his Belmont office.

But the organization's radical public image also rests heavily on its stands against such institutions as Social Security, public education and nation-wide suffrage. It frequently sparks the interest of the press by claiming that elaborate conspiracies are responsible for the Equal Rights Amendment, the Presidential candidacies of George McGovern and Nelson Rockefeller, and the fluoridation of our public water supply.

Many Americans also associate the Society with the Ku Klux Klan, Nazism, racism, anti-Semitism, and book burning.

Regardless of political stance, however, most observers agree that the Society--which reached its height in the mid-'60s--is now more an interesting relic than a strong political force. McManus likes to say that the organization was partly responsible for the nation's electoral surge to the right in 1980, but most analysts of popular opinion doubt that.

One critical political activist even suggests that the country's conservative shift--if it can still be called that--has actually hurt John Birch. "They represent the extreme right of the past. People identify with the Moral Majority more so than the John Birch Society. I actually think the fact that the new right has become a significant movement has hurt them."

The first turning point in the group's fortunes occurred in 1964 at the Republican National Convention, when Nelson Rockefeller appeared on coast-to-coast television to accuse the John Birch Society of being both Nazi and Communist sympathizers.

McManus says repeatedly that the John Birch Society has been "victimized" by that and other incidents. That may be so. A negative media blitz against the Society escalated just after it began to establish a sense of legitimacy the public had never before allowed. Since then, the Society has tried to rebuild itself by softening some of its earlier stances while still maintaining that a decentralized powerless national government will cure society's ills.

Because of its newer emphasis on purely political issues, McManus can not understand why the public still associates the Society with book burning. "We've been victimized by book burning," he explains. "I suppose some books deserved to be burned, but it's not our business to go about burning them. It hasn't been done in any organized fashion. It's not a program of ours. Our program is for a better world."

Founded in 1958 by Belmont resident Robert Welch--a native North Carolinian and part owner of the Welch Candy Company which produces Sugar Daddy and Sugar Babies--the Society was named for John Birch, an army intelligence officer killed by communists in China just after World War II.

"Robert Welch decided to form an information service for the American people. John Birch is an educational institution," McManus says. "We preach less government, more responsibility and, with God's help, a better world to live in. We are therefore opposed to communism, but we are just as much opposed to collectivism." McManus defines collectivism to be "big government, small people...socialism."

John Birch's Belmont headquarters are quiet enough. There's a receptionist or two. The carpet has a dull, worm-out and lifeless look. McManus's cramped office is strewn with assorted books, papers, and memorabilia, and on the wall hangs a portrait of Marine General Chester Puller, a Korean War hero.

Outside, most passersby don't even know what organization occupies the plain-looking building, let alone what views the John Birch Society actually promotes. And many of those familiar with the Society don't think about it much.

Yet despite the falloff in membership and the tranquil surroundings, McManus insists that the John Birch Society is thriving. It occupies three full buildings in the Belmont area alone. It has a national payroll of more than 175. Through its Western Islands Publishing Company, the Society prints four magazines, each with circulation hovering around 45,000. McManus one of the few official spokesmen for the Society--writes a syndicated column published in more than 100 county newspapers, although few big city papers run "The Birch Log." Recently, McManus has appeared on CBS's "Nightwatch" and is also scheduled for "PBS Latenight."

"Latenight" produce: Bill Pace says he asked McManus to be a guest on the show because, "We haven't heard from them in a long time. Their being on the show is more of an update. We are always looking for groups which are controversial in nature."