FROM AROUND 1960 to 1990, the leaders of American conservatism sought to purge the right of its ancient bigotries: antisemitism, racism and nativism. Their success was instrumental in convincing swing voters that conservatives could be entrusted with national power. Since the end of the Reagan administration, however, American conservatives have been quietly rehabilitating views confined for a generation to the fringe.

Consider the conspiracy theories of Pat Robertson, the white man's answer to LouisFarrakhan. In his 1991 book "The New World Order," Robertson argues that a secret cabal of international bankers, Freemasons and occultists has been responsible for the French and Russian Revolutions and the creation of the Federal Reserve. While Robertson is careful to stress his support for the state of Israel, he sees Jewish bankers behind all sorts of conspiracies: "It is reported that in Frankfurt, Jews for the first time were admitted to the order of Freemasons. If indeed members of the Rothschild family or their close associates were polluted by the occultism of Weishaupt's Illuminated Freemasonry, we may have discovered the link between the occult and the world of high finance."

One of the most familiar antisemitic libels is the claim that certain wealthy Jews, carrying out a long-range plan, have been behind both "monopoly capitalism" and "godless communism." In his 1991 book, Robertson repeatedly claims that Jewish bankers on Wall Street, seeking to create a mystical "new world order," backed the Bolsheviks: "What the average man and woman find so difficult to understand, however, is how a Wall Street banker such as Jacob Schiff of Kuhn, Loeb and Company could personally transport $20 million in gold to help salvage the near-bankrupt, fledgling communist government of the new Soviet Russia." Compare this with the following, from "Pawns in the Game," a Canadian neo-Nazi tract of the 1950s: "{Hitler and his associates} produced masses of documented evidence . . . to prove Communism was organized, financed, and directed by powerful, wealthy, and influential Jews . . . to further their secret ambitions to bring about the Messianic Age." According to the leader of the Christian Coalition, international high finance stood behind not only Lenin but John Wilkes Booth. Says Robertson, "it is my belief that John Wilkes Booth, the man who assassinated Lincoln, was in the employ of the European bankers."

In the 1950s the late conservative thinker Russell Kirk had the courage to make fun of the John Birch society's theory that President Eisenhower was a closet Red. "Eisenhower isn't a communist," Kirk said, "He's a golfer." By contrast, not one of today's timid conservative intellectuals has dared to mock Robertson, the powerful leader of the Christian Coalition. William F. Buckley, Jr., who drove Birch leader Robert Welch from the ranks of the respectable right, has repeatedly defended Robertson, even though the latter's claim that a "tightly knit cabal" of Satan-worshipping occultists is secretly running the United States through the Council on Foreign Relations makes Bircher conspiracy theories look tame. Other mainstream conservatives such as William Bennett and Midge Decter are doing their best to change the subject from Robertson's bizarre views by accusing critics of the religious right (many of them Jews) of anti-Christian or anti-religious bias. (In the same way, defenders of Farrakhan accuse his critics of racism.)

In addition to defending conspiracy theorists like Robertson, the right is showing a new receptivity to pseudo-scientific theories of racial inequality. Recently the flagship journal of the conservative movement, National Review, ran a rave review of Phillipe Rushton's "Race, Evolution, and Behavior." The enthusiastic reviewer summarizes Rushton's theory thus: "Orientals are more intelligent, have larger brains for their body size, have smaller genitalia, have less sex drive, are less fecund, work harder, and are more readily socialized than Caucasians; and Caucasians on average bear the same relationship to blacks . . . ." The book is already a word-of-mouth hit on the conservative circuit.

Phillipe Rushton is an obscure professor of psychology in Western Ontario who received more than $250,000 between 1986 and 1990 from the Pioneer Fund, a foundation established in 1937 by American supporters of eugenics who sought to encourage "race betterment" in America through the reproduction of descendants of "white persons who settled in the original thirteen colonies prior to the adoption of the Constitution and/or from related stocks." The American eugenics theorist Frederick Osborn, one of the founders of the Pioneer Fund, called the Nazi eugenics program the "most important experiment which has ever been tried."

Unlike the little-known Rushton, Charles Murray is a celebrated and respected mainstream conservative expert on social policy. Now Murray, who argued against welfare in his 1984 book "Losing Ground," has co-authored a book with the late Richard Herrnstein, a Harvard psychiatrist who argued for decades that IQ scores prove that blacks, on average, are inherently mentally inferior. In the much-hyped "The Bell Curve: Intelligence and Class Structure in American Life," Herrnstein and Murray write that "The most efficient way to raise the IQ of a society is for smarter women to have higher birth rates than duller women." Welfare should be abolished, they argue because it "subsidizes birth among poor women, who are disproportionately at the low end of the intelligence distribution."

With Murray and Herrnstein, conservative concern about the "dilution" of American culture by Third World immigrants is joined by a new rationale: concern about preservation of the American gene pool from contamination. In "The Bell Curve" Murray and Herrnstein go so far as to argue that "an immigrant population with low cognitive ability" is having what they call a "dysgenic" effect on America's gene pool: "Latino and black immigrants are, at least in the short run, putting some downward pressure on the distribution of intelligence." Murray and Herrnstein conclude: "Since the main ethnic groups differ in average IQ, a shift in America's ethnic makeup by itself would lower the average American IQ ... . {T}he shifting ethnic makeup by itself would lower the average American IQ by 0.8 per generation."

A century ago, alarmed Anglo-American nativists were expressing similar concerns about the influx of "feeble-minded" immigrants with strange names like Murray and Herrnstein. Then as now, pseudo-science disguised social prejudice: 83 percent of the Jewish immigrants given IQ tests at Ellis Island in 1913 by the eugenic theorist H. H. Goddard were classified as "feeble-minded." Murray tries to downplay Goddard's work by saying that "did not try to draw any conclusions about the general distribution of intelligence in immigrant groups." But, as Harvard biologist Stephen Jay Gould has pointed out, Goddard described his sample as "the great mass of 'average immigrants.' "

Murray and Herrnstein rely heavily in "The Bell Curve" on the writings of proponents of innate black inferiority like William Shockley, Arthur Jensen and Phillipe Rushton, each of whom has received hundreds of thousands of dollars from the Pioneer Fund. Two full pages of "The Bell Curve," in fact, are devoted to a defense of Rushton, arguing that the Canadian researcher "has strengthened the case for consistently ordered race differences" in intelligence, sexual drive and levels of parental affection. The Wall Street Journal devoted its entire Op-Ed page to excerpts from "The Bell Curve."

The message all of this is sending to conservatives is clear. If you want to blame the disasters of modern world history on the secret machinations of international Jewish high finance, or argue that black Americans are genetically programmed to be lazy and oversexed and to neglect their children, or speculate that "low-IQ" Mexican immigrants are having "dysgenic" effects on the American gene pool, then you will no longer be unwelcome in the conservative movement. The conservatives may even claim that you are a martyr to liberal prejudice.

The stakes in this "no enemies on the right" game are high. If Republicans make gains in Congress in the coming mid-term elections, and win the White House back in 1996, the GOP strategy of welcoming the formerly excluded far right will appear to be vindicated. The moderate conservative majority in the GOP will learn that their party has not been harmed, and may even be helped, by welcoming antisemitic conspiracy theorists, pseudo-scientific racists and nativists back into the fold. For the short-sighted opportunism of the conservatives, all of America may eventually pay a heavy price.

Michael Lind is a senior editor of Harper's magazine.