It accuses President Bush of being the "thief-in-chief, a trespasser on federal land, a squatter at the Oval Office" and calls for the marines to be sent in to evict him. It claims that the United States is a country that "goes out of its way to remain ignorant and stupid". And this week it became the number one bestselling book in the land.

No president has enjoyed such consistently high approval ratings as George Bush, which makes it even more remarkable that Stupid White Men by documentarist, journalist and political activist Michael Moore should be enjoying such success. Published earlier this month, this week it hit the number one spot in the New York Times, Los Angeles Times and on Amazon. It has now gone into print for the ninth time.

Moore made the 1989 award-winning documentary Roger and Me, about his pursuit of the then chairman of General Motors to question him about his decision to close down a factory that put thousands out of work.

He has created an Emmy-winning television series, TV Nation, and was a major campaigner for Ralph Nader in the 2000 presidential election. But Stupid White Men is the first time he has had quite such an obvious effect on the public debate. The book, serialised in Guardian Weekend on Saturday, is an energetic rant about the state of the nation with the president as its number one target. Moore calls for the United Nations to overthrow the "Bush family junta" and describes the president as the "Idiot-in-Chief".

He tells his readers: "The bad guys are just a bunch of silly, stupid white men. And there's a helluva lot more of us than there are of them".

Moore is elated by the success of the book. "People have had it with keeping silent for the past six months," he wrote in an email to supporters. "They resent having felt like if they chose to question what the government is up to or, God forbid, dissent, they would somehow be considered unpatriotic."

Margie Ghiz, owner of Midnight Special bookshop in Santa Monica, where the book has been selling fast, said yesterday: "It's a relief to many people to have this kind of thing said."

How long the book remains at its elevated position remains to be seen but US book buyers at the moment seem anxious to buy any title with a racial epithet attached: Nigger by Randall Kennedy is number six on the LA Times bestseller list.