When I was a teenager, my American girlfriend at the time gave me Ayn Rand's cult novel Atlas Shrugged to read. It changed her life, she said. It changed mine, too. She was not my girlfriend by the morning. It was the most unpleasant thing I'd ever had the misfortune to read.

As a work of literature, Atlas Shrugged is drivel, and not simply because it is so up itself with its own perceived radicalism; fundamentally, all propaganda is drivel, even if it is propaganda in a good cause. Rand's cause was to celebrate what she called "the virtue of selfishness", to denigrate the poor as scroungers and to celebrate the muscular individualism of the creative heroes of capitalism. Altruism, she contends, is "complete evil". The question she poses: what would happen if all the bankers and captains of industry went on strike? What would happen if these Atlas-like gods, who hold up the world, decided one day to shrug and refuse to support everyone else? Then the world would be buggered, she contends. Atlas Shrugged is cheap pornography for the nastiest side of capitalism.

"The reason I got involved in public service, by and large, if I had to credit one thinker, one person, it would be Ayn Rand," said Mitt Romney's now running mate Paul Ryan four years ago. He also admitted he made all his interns read Atlas Shrugged, dishing them out as Christmas presents.

But here's the political problem for Ryan. Many were queasy when George Bush cheesily described Jesus as his favourite philosopher, but at least he knew his market. In contrast, few books can be as hostile to the Christian faith as Atlas Shrugged. For Rand, the good Samaritan was not simply a chump: he was in fact doing something wicked. We are saved only by selfishness. So how can an American politician, who has described himself as a "staunch Catholic" and in what is supposed to be an electorate dominated by Christian values, side with one who so thoroughly rejected all the teachings of Jesus?

Ryan has now predictably backtracked. "I reject her philosophy. It's an atheist philosophy. If somebody is going to try to paste a person's view on epistemology to me, then give me Thomas Aquinas." By the way, this is the same Thomas Aquinas who insisted that, "Man should not consider his material possession his own, but as common to all, so as to share them without hesitation when others are in need," thus espousing the very collectivism that Rand so loathed.

Words are cheap, especially on the campaign trail. By your deeds shall you know them. And Ryan's deeds, and in particular his budget plan for slashing the role of the state, are pure Rand, as a group of Jesuits from Georgetown University have insisted: "Your budget appears to reflect the values of your favourite philosopher, Ayn Rand, rather than the Gospel of Jesus Christ. Her call to selfishness and her antagonism toward religion are antithetical to the Gospel values of compassion and love." The US Catholic bishops' conference, not well-known for its progressive politics, has said much the same.

It feels odd to be arguing that there ought to be more religion in US politics. In many ways, I'd prefer there to be a lot less. And certainly a lot less of the hard-right hogwash that borrows the wardrobe of Christianity but has no intention of being subject to its moral values. Jesus said nothing whatsoever about homosexuality or abortion. He said a great deal about poverty and our responsibility for the vulnerable. Which is why Paul Ryan is little more than Ayn Rand in Christian drag.

Ironically, he is a "second-hander" – Rand's terminology for those who take their values, prêt-à-porter, from others. The trouble is that Christianity in the US has become so widely hijacked by the right that not enough people will actually notice. As the Ryan case aptly demonstrates, the Christian right is neither: that is, Christian nor right.