.
Trump told the heckler to shut up because he had no intellectual tools with which to deal with him.
He had to sink to the heckler’s level (or more likely always is at that level)
.
Cruz would debate him? C'mon. If Cruz wants to set up a debate and invite them, that would be the way to do it. But to let them take over a rally with their agenda? That's enabling bullies.
Gotta disagree. I think Trump clearly has the intellectual tools to which you refer.
But maybe more importantly for a demagogue, he also has the tools of a "reality TV" superstar, meaning that he knows what will sell best with his audience -- many members of which no doubt fervently enjoy the entertainment pablum provided by The Apprentice, Survivor and similarly execrable TV fiction.
In other words, telling the guy to "shut up" may have been simply a viable political equivalent to Trump's "you're fired" shtick.