Movements on the rise are also forced to shape and sharpen their ideas, to formulate and test their policies in the news media and academia, or out of the spotlight in local precincts and party primaries. The philosopher and economist Friedrich A. Hayek, whose writings helped shape the modern right, said the free-market ideal most “progressed” when it was “on the defensive.” That encounter with reality, of trying to proselytize and govern amid an enemy more powerful than you, is a vital teacher. In that classroom, movements learn what to think, what to do, and how to do it. Once they graduate, they’re ready not only to seize power but also to exercise it.

Movements long ensconced and habituated to power — such that when their leaders are out of office, their ideas still dominate — get out of that practice. They lose touch with that external reality of their opponents. The impulsion outward disappears; they grow isolated and doctrinaire, more sectarian than evangelical. Arguments their predecessors had to sweat their way through soften into lazy nostrums or harden into rigid dogmas. The free-market ideal, Hayek says, “became stationary when it was most influential.”

Now the movement’s problem is the opposite of when it was in its ascendancy. Its leaders may control all the elected branches of the federal government, as the Republicans do now and as the Democrats did under Jimmy Carter, and many of the state governments, but they no longer control or set the terms of political debate as much as they once did. Their power in government conceals their slipping hold on public legitimacy.

It’s not that the character of the personnel has changed: The Tea Party supporter is no more zealous than Barry Goldwater, and on any given day, Ronald Reagan could be as fuzzy and foggy as Donald Trump. It’s the context that has changed. Yesterday’s conservative wrote and read his Bible in the crucible of defeat; today’s recites his catechism in a cathedral of success.

It’s no surprise, then, that the Republican Party should now find itself uncertain about what to do. After 40 years in Zion, it has lost the will and clarity it acquired while wandering in the desert. The movement has lost the constraint of circumstance.

It’s too early to declare the repeal of Obamacare dead. Other constraints — the need to cut spending to pay for and justify the tax cuts that have always been the North Star of the movement — may make themselves felt and push even the most extreme forces in the Republican Party to return for a compromise. But the chaos surrounding health care, like that of the Trump administration, is a sign of further disjunction to come.