Here’s an excellent exposé at Salon by Alexander Zaitchik, on one of the main ideological sources for Glenn Beck’s extremist rhetoric — a paleo-right crank connected to the John Birch Society named Cleon Skousen, whose bizarre book (“The 5,000 Year Leap”) Glenn Beck has been relentlessly promoting: Meet the man who changed Glenn Beck’s life.

In reality, however, the so-called 912ers were summoned to D.C. by the man who changed Beck’s life, and that helps explain why the movement is not the nonpartisan lovefest that Beck first sold on air with his trademark tears. Beck has created a massive meet-up for the disaffected, paranoid Palin-ite “death panel” wing of the GOP, those ideologues most susceptible to conspiracy theories and prone to latch on to eccentric distortions of fact in the name of opposing “socialism.” In that, they are true disciples of the late W. Cleon Skousen, Beck’s favorite writer and the author of the bible of the 9/12 movement, “The 5,000 Year Leap.” A once-famous anti-communist “historian,” Skousen was too extreme even for the conservative activists of the Goldwater era, but Glenn Beck has now rescued him from the remainder pile of history, and introduced him to a receptive new audience.

Anyone who has followed Beck will recognize the book’s title. Beck has been furiously promoting “The 5,000 Year Leap” for the past year, a push that peaked in March when he launched the 912 Project. That month, a new edition of “The 5,000 Year Leap,” complete with a laudatory new foreword by none other than Glenn Beck, came out of nowhere to hit No. 1 on Amazon. It remained in the top 15 all summer, holding the No. 1 spot in the government category for months. The book tops Beck’s 912 Project “required reading” list, and is routinely sold at 912 Project meetings where guest speakers often use it as their primary source material. At one 912 meet-up I attended in Florida, copies were stacked high on a table against the back wall, available for the 912 nice price of $15. “Don’t bother trying to get it at the library,” one 912er told me. “The wait list is 40 deep.”

What has Beck been pushing on his legions? “Leap,” first published in 1981, is a heavily illustrated and factually challenged attempt to explain American history through an unspoken lens of Mormon theology. As such, it is an early entry in the ongoing attempt by the religious right to rewrite history. Fundamentalists want to define the United States as a Christian nation rather than a secular republic, and recasting the Founding Fathers as devout Christians guided by the Bible rather than deists inspired by the French and English philosophers. “Leap” argues that the U.S. Constitution is a godly document above all else, based on natural law, and owes more to the Old and New Testaments than to the secular and radical spirit of the Enlightenment. It lists 28 fundamental beliefs — based on the sayings and writings of Moses, Jesus, Cicero, John Locke, Montesquieu and Adam Smith — that Skousen says have resulted in more God-directed progress than was achieved in the previous 5,000 years of every other civilization combined. The book reads exactly like what it was until Glenn Beck dragged it out of Mormon obscurity: a textbook full of aggressively selective quotations intended for conservative religious schools like Utah’s George Wythe University, where it has been part of the core freshman curriculum for decades (and where Beck spoke at this year’s annual fundraiser).

But more interesting than the contents of “The 5,000 Year Leap,” and more revealing for what it says about 912ers and the Glenn Beck Nation, is the book’s author. W. Cleon Skousen was not a historian so much as a player in the history of the American far right; less a scholar of the republic than a threat to it. At least, that was the judgment of J. Edgar Hoover’s FBI, which maintained a file on Skousen for years that eventually totaled some 2,000 pages. Before he died in 2006 at the age of 92, Skousen’s own Mormon church publicly distanced itself from the foundation that Skousen founded and that has published previous editions of “The 5,000 Year Leap.”

As Beck knows, to focus solely on “The 5,000 Year Leap” is to sell the author short. When he died in 2006 at the age of 92, Skousen had authored more than a dozen books and pamphlets on the Red Menace, New World Order conspiracy, Christian child rearing, and Mormon end-times prophecy. It is a body of work that does much to explain Glenn Beck’s bizarre conspiratorial mash-up of recent months, which decries a new darkness at noon and finds strange symbols carefully coded in the retired lobby art of Rockefeller Center. It also suggests that the modern base of the Republican Party is headed to a very strange place.

Read the whole thing; there’s much more. This is very disturbing stuff, and it explains a lot about Beck’s demagoguery.