Mr. Cruz knows either Mr. Rubio or Mr. Walker could fight him in his brackets. But he thinks they’ll mostly compete in the moderate bracket, where Mr. Bush will get roughed up. Mr. Cruz won’t win moderates, but that underscores his point: A moderate GOP nominee won’t win the general election because parts of the Republican base won’t come out.

Mr. Cruz knows his reputation as the angry, surly face of the dark side of conservatism. He’s the government-shutdown artist, the living answer to the question “What if Joe McCarthy went to Harvard Law?” He says it’s a caricature.

He once noted to me in conversation that when people on TV call him angry and snarling, they never show video to illustrate the point. He says there is no angry, snarling video because he isn’t angry and doesn’t snarl. He never throws mud, he says, and won’t. He sees himself as a happy warrior.

I don’t think the snarling image thing is his main problem. He has two others.