Julius Krein is the editor of American Affairs.

Alvin S. Felzenberg’s biography of William F. Buckley Jr. arrives just after the political and intellectual collapse of Buckley’s conservative project. Although Felzenberg does not specifically address the 2016 campaign, it is impossible to read his book without looking for clues that might explain Donald Trump’s hostile takeover of the Republican Party. Indeed, “A Man and His Presidents” is a rather poor biography of Buckley, consistently preoccupied with the trivial at the expense of the significant. Yet the book offers some important and perhaps unintended insights into the unraveling of the conservative movement.

The principal weakness of Felzenberg’s biography is that it contains little in the way of serious intellectual history. A reader otherwise unacquainted with Buckley’s work would come away with the impression that he never wrote anything beyond acerbic one-liners and forgettable novels. And if Felzenberg’s Buckley wrote little, he read almost nothing. Important debates between traditionalists and libertarians — and Buckley’s role in securing their temporary resolution under the banner of “fusionist” conservatism — receive shockingly scant attention. The influence of neoconservatism is totally ignored. And aside from brief accounts of interactions with fellow National Review editors, there is little meaningful discussion of Buckley’s relationships with other leading conservative intellectuals.

Without any coherent treatment of the deeper intellectual currents shaping Buckley’s positions, there is nothing to hold the narrative together. The book is less a biography than a breezy history of the major political events that occurred during Buckley’s lifetime. And since Buckley’s career spanned a period from before World War II to the Iraq War, no single episode can be examined in any depth.

This problem is compounded by the fact that — the book’s grandiose title notwithstanding — Buckley exerted a significant degree of influence on only one president, Ronald Reagan. He loathed Dwight Eisenhower; was considered a nuisance by Richard Nixon, Gerald Ford and both George Bushes; and was shut out of Barry Goldwater’s campaign. Even in his discussion of the Reagan administration, however, Felzenberg inexplicably focuses on the least important material. He spends more time discussing Buckley’s bizarrely flirtatious correspondence with Nancy Reagan than on the administration’s trade policy or Iran-contra. He devotes pages to Buckley’s momentary contretemps with Reagan over whether the president would attend a National Review anniversary dinner — as if it mattered then, much less now. Likewise, the decades-long friendship between Buckley and Henry Kissinger is mentioned frequently, but if the two ever had a substantive conversation about detente, or anything else, Felzenberg is apparently unaware of it.

Those genuinely interested in Buckley’s life and his influence on conservative intellectual debates would probably prefer John B. Judis’s “William F. Buckley, Jr.: Patron Saint of the Conservatives.” Nevertheless, “A Man and His Presidents” offers some insight into the collapse of Buckley’s conservative movement precisely because its weaknesses as a biography coincide with the weaknesses of movement conservatism.

It is unlikely that Felzenberg sought to diminish the reputation of his subject, but that is the effect of his work. The “political odyssey” of the subtitle is a fairly simple one: In Felzenberg’s account, Buckley inherited a constellation of attitudes from his father, including total opposition to the New Deal, strident anti-communism and staunch Roman Catholicism. The young Buckley also shared his father’s racism, anti-Semitism and isolationism (Buckley joined the America First Committee before World War II, though Felzenberg is quick to point out that John F. Kennedy was a member, too). Over time, Buckley either shed or moderated all of these views. He began his career at National Review by ranting against Eisenhower and defending segregation. By the end, he had become a respected elder statesman willing to criticize McCarthyism and accept the New Deal. Felzenberg describes this process as one of intellectual and political maturation, by which the prudent counsels of figures such as Whittaker Chambers slowly impressed themselves upon the brash radical.

But there is another interpretation Felzenberg does not consider: that 20th-century American conservatism simply never made any sense. Far from a coherent program of high principle, it was always a largely accidental combination of inherited reflexes and political opportunism. There is certainly much more to conservative thought than what is treated in Felzenberg’s biography. None of it, however, changes the fact that conservatism’s political trajectory parallels Buckley’s rather embarrassing intellectual journey: One by one, its tenets are admitted to be little more than “irritable mental gestures,” to use Lionel Trilling’s famous phrase, until it is reduced to the most simplistic form of Reaganomics. The one exception is anti-communism, which disappeared with the Soviet Union. It is telling that Buckley’s writing career begins with “God and Man at Yale,” a rousing and idealistic — if not particularly thoughtful or effective — defense of tradition, and ends with grumbling about deficits.

The history preferred by conservatives, including Buckley, is a version of Felzenberg’s maturation thesis, a purging of crackpots and fringe prejudices to allow the light of “true conservatism” to shine more brightly. Yet that is true only if there is something illuminating at the core. Buckley’s conservatism, as portrayed by Felzenberg, however, rather resembles Gertrude Stein’s Oakland: Cranks of diverse kinds pass in and out of it, but there’s no there there. And while the purging of crackpots ought to be celebrated, what if all that remains are talk show hosts, sycophants and second-rate economists?

Some movement grognards who still hope for a restoration of Buckley’s conservatism have appealed to his example to reproach President Trump. But such comparisons are unlikely to impress anyone who reads Felzenberg’s book. Whatever one might think of the current administration, Buckley was, at times, all the immoral things that Trump is accused of being. Felzenberg even undercuts the legend of Buckley’s greatest purge, noting that he went to considerable lengths in private to repair relations with the John Birch Society’s leader, Robert Welch, even after denouncing him in public.

“A Man and His Presidents” is most successful as a reminder that American politics has not changed as much as it sometimes seems — political discourse in the 1950s was rather ridiculous, too, with Welch accusing the president of secret collaboration with Russia, for example. In certain ways, Buckley even prefigured some of the worst tendencies of today’s politics. He was one of the first campus provocateurs, for instance, and his frequent use of biting personal insults would fit well in an obnoxious Twitter feed. One noticeable difference, however, is that Buckley repeatedly sued people who called him a Nazi, and occasionally he won.

Buckley was also able to maintain meaningful friendships and discussions with ideological opponents, something that occurs rarely today. He criticized every president of his own party and even broke with many National Review editors on the Iraq War.

Perhaps Buckley succeeded because his personality was always larger than his ideology. At a certain level, he seems to have understood that politics was more than ideology, too. Felzenberg does an admirable job capturing these aspects of Buckley’s career, which deserve to be recalled more often today.