In Boot’s initial telling of his story, conservatism is inspiring, principled, responsible, morally demanding, wise. It collapses only when Donald Trump assaults the citadel from the outside, like a rampaging army or deadly contagion. The heroes of this narrative are Boot and his allies, who take a noble if futile stand against this evil invader in the name of their conservative ideals.

But the story Boot recounts in the concluding chapters is different. Now, in light of the present, Boot sees rot on the right that has been there from the start — in William F. Buckley’s pro-segregationist editorials in National Review, in Phyllis Schlafly’s best-selling screed “A Choice Not an Echo,” in Newt Gingrich’s take-no-prisoners tenure as speaker of the House, in rabble-rousing talk radio shock jocks and above all in the polarizing and poisonous influence of Fox News. All of this leads Boot to conclude that “extremism is embedded in the DNA of the modern conservative movement,” as if Trump is where the movement had been headed, or fated to end up, from the start.

This implies that it’s mostly Boot, and not conservatism or the Republican Party, that has changed. Scales have fallen from his eyes. Once he was blind, but now he sees. He even adopts the quasi-religious language of the social justice left in describing an intellectual awakening about the persistence of racism and sexism in American society.

But then what are we to make of Boot’s epilogue, where he lists the policies he now supports and ends up saying pretty much the same thing he always has? He’s fiscally conservative and socially liberal, favors free markets, free trade and high rates of immigration, and internationalism in foreign policy backed up by the threat (and generous use) of military force around the globe. These were exactly Boot’s views in 1985, 1995, 2005 and 2015.

The one thing that clearly has changed is that Boot now regards the Iraq war, which he giddily championed in explicitly imperialistic terms, as a mistake — one that has taught him the “limits of American power.” That’s refreshing, though it would have been nice to see more evidence that this lesson is being translated into greater restraint about America’s conduct in the world generally. Instead, we get reflexively hawkish comments about America’s Obama-era and present-day dealings with Iraq, Afghanistan, Syria, North Korea, China and Russia. Many of these statements follow from the same misguided assumptions that convinced Boot and so many others that a war of choice to oust Saddam Hussein was a splendid idea.

One wonders how the book would have turned out had Boot taken a few more steps back from the fray, to place his lifelong ideological commitments in a wider frame. In that case, he might have seen that the principles and assumptions that first drew him to the Republican Party were not especially “conservative” at all. They were, instead, the expression of a particularly bellicose strand of Cold War liberalism that migrated from the center-left to the center-right in the aftermath of the Vietnam War, when a shellshocked Democratic Party temporarily abandoned it. By the election of Bill Clinton in 1992, this brand of muscular, centrist liberalism was back, dominating (with minor differences in emphasis) both parties.