I very much enjoyed reading the “Exit Right: The People Who Left the Left and Reshaped the American Century” (Simon & Schuster, 2016), which details the movement of six very different individuals from the political left to the political right. The book’s subjects are Whittaker Chambers, James Burnham, Ronald Reagan, Norman Podhoretz, David Horowitz and Christopher Hitchens, each of whose apostasy is explicated in a chapter.

The subject matter intrigued me. As a graduate student at New York University, I seriously considered writing a dissertation on the history of conservatism in America (I switched to another topic when it became plain that the subject matter would not earn me a teaching job anywhere). Reading this book was a pleasure, in no small part, because it allowed me once again to read about the intellectual tumults of the second half of the 20th century, which birthed new voices on the right.

Stylistically, “Exit Right” is a beauty. Oppenheimer is a man of the left, but he does not checker his book with snark or condescension. He respectfully details each man’s life up to and through their political conversion. The book’s prose is mellifluous and engaging, which is no mean feat when you consider the subject matter: the evolving ideas of six men—most of whom are dead.

But what important subject matter it is, for as William Faulkner put it: “the past is never dead. It’s not even past.” Both the right and the left continue to experience the reverberations of the political defections of Chambers, Burnham and the rest to this day. To a degree, all of us continue to argue within the bounds they drew and divide ourselves according to the stands they took.

A complex amalgam of experiences and motivations drew each of the profiled individuals to make their respective journeys from left to right. For Chambers and Burnham, two men of very different casts of mind, the incompatibility of art with communism put them off the left. Reagan’s change of heart was more deliberate, flowing from his growing enamoration with the idea of America, which came from his travels as a General Electric pitchman. Reagan also was driven rightward by the attempts of communists to hijack Hollywood guilds. Podhoretz, meanwhile, was a lost man in his twenties and thirties hunting for a purpose for his generation. He found one in the well of his wounded soul, discoursing on “white guilt,” Jews’ place in America and more. Horowitz and Hitchens, who ostensibly share little more than the H’s in their last names, together took right turns after those they knew felt the brunt of political evil.

But none of these right turns were fated to happen. If Trotsky had not been so heavy-handed and condescending, Burnham might never have rejected Marxism and ended up editing National Review. Who knows?

One common thread is that each man was turned off by the left’s dogmatism. Hitchens was appalled when fellow leftists justified the Ayatollah Khomeini’s fatwa against Salman Rushdie, as they insisted on the primacy of “respecting cultural differences and sensitivities.” As thoughtful people, Chambers and the rest could not live with such toadying and rationalizations.

In this respect, “Exit Right” offers a lesson that still rings true today: defending the indefensible ultimately fails. Ideologies and political movements remain vibrant only so long as their visions remain appealing and credible.

Oppenheimer’s book is a fascinating intellectual history, but its stories also remind us of the value of humility. As he writes:

We know belief is complicated, contingent, multi-determined. But do we really know it? Do we feel it? Do we act as though it’s true, with the humility that such knowledge would entail? Not most of us. Not most of the time[T]he grounds of our beliefs are more contingent than we could possibly account for.