It's important, as PJ O'Rourke says in this good-naturedly cantankerous polemic, to shout at the radio now and again. He listens to National Public Radio rather than fellow rightwinger Rush Limbaugh, because "when I'm in the car, I want the only one shouting to be me". There's no point being preached to when you're already a convert.

It's in this spirit that Observer readers should pick up this book, because when O'Rourke's not making jokes or being gleefully ridiculous  saying that foreign aid is like spoiling your kids, that as a conservative he hates fun, and that Obama carries the "white man's burden"  he makes a heartfelt argument for what's at the core of Republicanism: the idea that government is too big.

In case you missed that argument, there are some subtle signposts, such as the third section of the book being called "Putting Our Big, Fat Political Ass On a Diet". There are some sensible bits, such as an outcry over a penny costing almost two cents to make, and less sensible bits, such as the suggestion that global warming has been "tarted up", or that state-funded healthcare results in the guy from the Department of Motor Vehicles doing your heart bypass.

In short, O'Rourke thinks America is in too much debt, the government needs to butt out of people's lives, and the people helping the country most are Wall Street traders coughing up taxes for as long as it takes before they're thrown in jail. This is backed up by quotes from Adam Smith and stats on fiscal policy, although with O'Rourke refusing to keep a straight face for more than a line or two, it's hard to work out how much of it to take seriously.

Take a chapter called "Why I'm Right". In it, O'Rourke explains that he was brought up a Republican, became a Marxist in college due to cute beatniks, and switched sides as soon as he got a job. He made the transition back the night his wife gave birth: "Suddenly I was an opponent of change."

This isn't to say his values don't run deep  O'Rourke's a libertarian through and through  but don't buy this book looking for careful deliberation. Buy it because agreeing is much less fun than shouting.