The test of a first-rate intelligence, F Scott Fitzgerald once said, "is the ability to hold two opposed ideas in the mind at the same time, and still retain the ability to function". Fitzgerald remains one of our greatest experts on the American scene, but I've never been a particular fan of this comment, because functioning under opposing ideas is also the test of a first-rate hypocrite.
It seems, for example, a fair description of Newt Gingrich's spectacular hypocrisy, as well as of the generous, philosophical tone some of the Republican faithful have taken toward this abdication of their supposedly foundational "family values".
Gingrich, who won the Republican primary in South Carolina at the weekend, has insisted that his sexual (mis)conduct does not affect his ability to serve as president, but this is not the stance that Republicans took against Bill Clinton 15 years ago.
Now we learn that even as Newt was hurling stones at Clinton with one hand, he was beckoning his mistress into his glass house with the other.
That a political candidate turns out to be power-hungry, opportunistic, and treacherous should not, in fact, surprise us. What is more worrying is how many voters who claim that family matters most are prepared to look the other way: partisan politics have so poisoned the American electoral system that cognitive dissonance has become a way of life.
Fitzgerald's magnificent 1922 satire of American monopoly capitalism and political corruption, The Diamond as Big as the Ritz, features a tycoon named (ironically and allegorically) Washington, a "Prometheus Enriched" who tries, when he is about to lose everything, to bribe God. God doesn't answer; Washington is destroyed. Gingrich has, naturally, told us sorrowfully that he has asked God's forgiveness for his transgressions.
British people often ask Americans like me to explain why my nation's politicians insist on their godliness, despite bagatelles like the Constitution's establishment clause enjoining the separation of Church and State. But Gingrich shows the answer: God is very handy for a Prometheus Enriched, because you can ask him a question and know he will never answer.
To paraphrase a far lesser-known line of Fitzgerald's, it seems that American politicians are just changing the channels of their avidity.
Sarah Churchwell is Professor of American Literature and Public Understanding of the Humanities at the University of East Anglia