“With Cruz, though, even the most fervent peroration always feels like a debater’s patter, an advocate’s brief…”

Enough, for one week at least, about the strange victories of Donald Trump. Let’s talk about the mysteries of his last real competitor, Ted Cruz.

On the surface, Cruz is a straightforward figure: The ideological zealot, the politician-as-activist, the unbending embodiment of True Conservatism. He’s the scourge of Obamacare, the bane of the G.O.P. establishment, the evangelical moralist with a flat-tax plan and a Reagan quote for every occasion. If Trump has dynamited Republican orthodoxy and tapped out nasty tweets from the rubble, Cruz has kept pace by promising to rebuild that same orthodoxy stronger than before.

In this framing, Cruz is basically Barry Goldwater come again, an ideological crusader who might still grab his party’s nomination, but whose general election prospects are limited by his own extremism.

I’ve used this framing myself, and it might be the best way to approach a Hillary-Cruz race. But it also seems inadequate to understanding Cruz’s strange ascent.

Start at the intuitive level. Despite what you may have heard, true belief is pretty common among politicians. Listen to Rand Paul talk about liberty or Marco Rubio dilate on the promise of America; watch Bernie Sanders rail against inequality or President Obama defend technocratic liberalism. They all radiate sincerity. Watch a Goldwater speech: you can tell the man believed it.

With Cruz, though, even the most fervent peroration always feels like a debater’s patter, an advocate’s brief — compelling enough on the merits, but more of a command performance than a window into deep conviction.

This doesn’t mean that Cruz’s conservatism isn’t sincere. But the fact that he seems so much like an actor hitting his marks fits with the story of how he became Mr. True Conservative Outsider in the first place. Basically, he spent years trying to make it in Washington on the insider’s track, and hit a wall because too many of the insiders didn’t like him — because his ambition was too naked, his climber’s zeal too palpable. So he deliberately switched factions, turning the establishment’s personal disdain into a political asset, and taking his Ivy League talents to the Tea Party instead.

Ross Douthat, “Who Is Ted Cruz?”, The New York Times (27 March 2016), SR11.