America has passed its peak, declared the brooding author Kevin Phillips, who spoke recently at a Barnes & Noble on the Upper West Side. The question, he posed, is just how far down the other side it has slid.

Mr. Phillips wrote “American Theocracy: The Peril and Politics of Radical Religion, Oil, and Borrowed Money in the 21st Century” (Viking), in which he distilled America’s problems down to the three ideas mentioned in the book’s title. “Some people say, ‘Well, you’re forgetting about terrorism,’ and my argument is that it is in many ways encompassed by a combination of radical religion and oil.”

Drawing analogies to previous leading world economic powers, he said: “It’s very tough for countries to face up to this kind of analysis.” If an author in the Edwardian period before World War I analyzed how the British Empire was going to decline, his views would likewise not have been welcome, he said.

Mr. Phillips offered yardsticks for showing when a world power had peaked and was “over the hill.” One is a tendency to go overboard in religion and “too enthused” about it. There is a national “disenlightenment” where science becomes subordinate to religion, he said. He gave the example of Galileo’s disagreement with the papacy to contemporary debates over creationism and stem cells.

Radicalized religion in America is a “seedbed of problems,” and the country shows signs of incipient theocracy, he said. Theocracy is not limited to John Calvin’s Geneva, or Massachusetts Bay of the Puritans, or Utah of the early Mormons in the 19th century, he said.

Mr. Phillips argued that today in America, as with previous leading world powers such Rome or Spain, “a millennial mood” has arisen, along with a sense of a great showdown and talk of Armageddon. “There was this sense as the barbarians were about to overrun Rome,” he said.

At this point in his lecture, an audience member’s cell phone rang. “That’s George Bush calling,” Mr. Phillips quipped. “He’s listening in,” an audience member shouted.

Mr. Phillips returned to discussing the millennial mood and said Protestants once referred to Phillip II of Spain as an anti-Christ: “There’s always an anti-Christ during these great showdown periods.”

He said a Newsweek poll around the millennium found that 45% of American Christians thought the battle of Armageddon would come and was real and roughly as many thought that the anti-Christ was alive and on earth at that point.

He continued with his American theocracy argument, saying religion has taken a role in American politics that it never had before. This was due, he said, to the rise of the South as the dominant force within the Republican Party. “The South has eaten the Republican elephant,” Mr. Phillips said. He further quoted poll numbers showing how in America, more so than in other countries, people think religious leaders should try to influence government decisions.

During the question-and-answer period, one person said that for most people, the principles of religion are very uplifting. “So what is wrong with a politician saying he gets guidance from religion?” she asked.

“You can state it that way, and it’s hard to disagree with,” Mr. Phillips said. “But you could have asked the same question in the Catholic Inquisition: ‘Isn’t religion a good thing?'” He elaborated by saying that religion may have been uplifting to many, but the church in Spain in the 16th and 17th centuries wanted to impose its beliefs on everybody else there.

“You’re talking about the fringe elements,” the questioner persisted.

“Well, the fringe elements are very powerful at the present time,” Mr. Phillips replied.

In late stages of great powers, there is invariably strategic and military overreach, the author argued. “They try to bite off too much or go too far, and wind up increasingly going into debt in order to manage this. Their ambitions are greater than their treasury.”

An audience member asked if Mr. Phillips saw hope for the Democratic Party. “Somebody told me that 60 years ago the Democrats sounded and looked like Woody Guthrie, and today they sound and look like Woody Allen,” the author said.

On the subject of Mayor Giuliani, Mr. Phillips said he didn’t personally care for the man, but it would help to transplant small parts of him into the Democrats: “He’s tough. These guys aren’t tough. They don’t have an instinct for the jugular. They have an instinct for the capillary.”

gshapiro@nysun.com