Trump saw the speech ahead of time.
I suppose he could have stopped it. But that would have been doing Ted a favor—and would have made Trump look bad.
So Trump did the generous thing and let Ted speak—KNOWING that Ted was going to be slitting his own throat.
Trump simultaneously DID THE RIGHT THING and destroyed an enemy. That has to be gratifying!
Giving convention opportunity to boo Cruz was good as a party-unifying and energizing tactic. Could have used more of ithis approach, actually. photos of Mitt, Jeb and Hillary could have been flashed on that massive screen for two minutes each. Maybe Kasich too.