There’s always been a strain of paranoia running through American politics. Back in the mid-1960’s, when the right felt powerless, the John Birch Society thrived. Today, when the left feels disinherited, liberals seize upon the conspiracy fantasies of Kevin Phillips, whose book “American Theocracy” is in its fifth week on The Times’s best-seller list.

Phillips’s method is pretty conventional for conspiracists — he takes a single issue or set of data points and constructs an all-explaining story line to show how hidden cabals are controlling America.

In the first part of “American Theocracy,” he describes the rise of the “fossil-fuels political alliance.” Dwight Eisenhower was “born in oil country” and in 1952 became the first Republican to sweep the Southern oil centers. Nixon too “had an oil-state childhood” and deepened oil’s influence.

Pretty soon, Republicans could count not only on energy and automobile producers but also on “secondary cadres” including “racing fans, hobbyists, collectors, and dedicated readers of automotive magazines, as well as the tens of millions of automobile commuters from suburbs and distant exurbs.”

By 1997, reasons were mounting to take over Iraq’s oil, Phillips asserts. “A near-final decision to invade seems to have been made in early 2001,” he adds, months before 9/11. The Iraq war was born.

The oil alliance melded with another hidden army, the “end-times electorate,” Phillips continues. Relying on the fact that millions of people read the “Left Behind” apocalyptic fantasy novels, Phillips asserts that 50 to 60 percent of Republicans believe in Armageddon and are influenced by the argument that the “destruction of the new Babylon” in Iraq will hasten the coming of the messiah.

Phillips says that the Bush White House sends messages to these Americans through “double-coding” in his speeches — phrases that mean one thing to secular America but contain hidden meanings to people with the “biblical worldview.” Phillips cites research showing President Bush used the phrase “I believe” 12 times in his 2004 G.O.P. convention speech — code for religious zealots.

Needless to say, Phillips’s book is rife with bizarre assertions. He writes that “many Orthodox Jewish females cannot even study the Torah,” that the Rev. Sun Myung Moon “has been close to the Bush family,” that the American Revolution was “in many ways a religious war.”

But his method is pretty standard. First, he takes advantage of the record of his liberal readers’ ignorance of evangelical communities to make ludicrous assertions. Second, as Jacob Weisberg noted in Slate, Phillips will begin a chapter making some grand accusation. Then he will depart on what Weisberg accurately calls “a pompous, pedantic history tour” of medieval mineralogy or 16th-century politics. Then, without presenting any evidence or answering any objections, he will repeat his accusation in stronger language.

Third, Phillips is a master of slicing reality so that it conforms to predetermined conclusions. To take one example among many, in 2002 the evangelist Franklin Graham organized a meeting to address the AIDS crisis. Graham said evangelicals should be ashamed of how slowly they’ve responded to the crisis, “I have to point the finger at myself and say, ‘I’m late.’ ” AIDS is not about homosexuality, he continued, “the danger is to all of us.” He praised Colin Powell’s efforts, even though Powell is a strong advocate of condoms. He accelerated what has become a strong evangelical mobilization against AIDS.

Philips writes about that meeting, but ignores all of this. Instead Phillips lumps the conference in with gay-bashing and writes, “Only Jesus Christ can bring about the societal change needed to stop AIDS, preacher Franklin Graham told a 2002 Washington conference.”

This is intellectual dishonesty on stilts. Nonetheless, Phillips’s books fly off bookstore shelves, and he’s given respectable platforms in the major media and at universities.

We’re at a moment when crude conspiracy mongering — whether it is academic papers on the Israel lobby or George Clooney’s “Syriana” — is emerging from the belly of the American establishment.

And while many informed critics have picked apart Phillips’s fantasies, other Americans, at once cynical and naïve, are willing to believe any whacked-out theory, so long as it focuses hatred on Bush.

It’s a funny way to run a theocracy.