He’s not insecure, but his base/supporters will look at him askance were he to nominate Sen. Cruz.
Says more about his base than Trump. Ted Cruz is a solid conservative and a good man. Unfortunately, he almost lost a statewide race in Texas to an unapologetic gun-grabbing far-leftist. In Texas. This doesn't bode well for his political future.
Probably time for Senator Cruz to look for a future career that doesn't require campaigning. I think he'd do conservatism well on the bench.