In "The Conservative Mind," David Brooks writes an astonishing retrospective:
Ronald Reagan embodied both sides of this fusion [of economic and traditional conservatism], and George W. Bush tried to recreate it with his compassionate conservatism. But that effort was doomed because in the ensuing years, conservatism changed.
Economic conservatives went into ascent, traditionalists into decline. That's Brooks' thesis, notwithstanding the raging popularity of, for one, social conservatism's Rick Santorum, whose party would now happily trade Mitt Romney--"Official Economic Conservative"--for him.
So there's that. But that's not what really astonishes. What does that trick is Brooks' assertion that "conservatism changed" post-Reagan; that pretty much all things conservative were humming along just fine when Brooks joined The Cause (at National Review) in 1984--only afterward came the ideological mudslide.
Indisputably, things got worse after Reagan. Supply-siding conservatives became ruthlessly anchored in their righteousness, as did the traditionalists (e.g. the Moral Majority). But to suggest that conservatism began its deterioration after Reagan is to ignore the entire, wretchedly conspicuous history of contemporary conservatism.
Loosely impelled in '64 by the Goldwater campaign and confederated by the 1970s and firmly entrenched by the Age of Reagan were the New Rightists--those social "traditionalists" who demagogically honed the political crafts of bigotry, buncombe artistry, misogyny, homophobia, Gantryism and obscurantism. Even Reagan had to work at tolerating them, and by '84 they were threatening to bolt.
Meanwhile, although certainly not the absolutist that today's economic conservatives are, President Reagan had entered office by championing the incoherence, contradictions, oversimplifications, anti-empiricism and ahistoricity of voodooing supply-side economics. In today's $16 trillion national debt and massive wealth inequality, we see the real-world results of theoretical economic conservatism.
Still, there's something else, there's something far more fundamental in how "conservatism changed," and it's something that Brooks barely references. He of course borrows his column's title from Russell Kirk's magisterially conceived and beautifully written The Conservative Mind (1953), in whose foreword to a revised edition Kirk is unmistakably alarmed:
[T]he conservative abhors all forms of ideology.... Such a priori designs for perfecting human nature and society are anathema to the conservative, who knows them for the tools and the weapons of coffeehouse fanatics.
Kirk wrote that in 1986, and he wrote it partly with a censorial eye toward those intensifying ideologues at National Review, which Brooks had joined two years earlier. It seems Brooks has been a frog in the heating pot ever since, and he's just now noticing that the water is boiling.