Though Cruz and Trump have not attacked each other, it’s obvious that they have criticisms in the drawer and prepared for use. This summer, Trump raised questions about Cruz’s Canadian birth and whether he was constitutionally eligible to be president. I asked him about this last week. Would he bring that up again? “I’ll only bring it up if he’s a final two,” said Trump…

Cruz also likes to debate, and when he does, he doesn’t simply speak to the beauty of his arguments alone. He also dismantles the positions and questions the motivations of his opponents.

So this is no small act of restraint. Additionally notable is that Cruz’s colleagues said this restraint was the key thing that Cruz lacked in his fight against the Affordable Care Act. He had no strategy, they argued. He was an ideologue whose passions (whether they were for self-elevation or against the bill) propelled him into a foolish fight with no possibility of a successful outcome. “I didn’t go to Harvard or Princeton, but I can count,” said Sen. Bob Corker of Tennessee at the time. The defunding box canyon is a tactic that will fail and weaken our position.”

Were Cruz an ideologue compelled to speak out against wrongs of the kind he has identified in the Senate, he would have spoken out already quite a lot about Trump. But Cruz knows the difference between a losing fight where he gains greater glory among the voters he wants, like the Affordable Care Act shutdown fight, and a fight that might threaten his relationship with those very voters.