I heard the entire show.
To suggest that Levin and Cruz "discussed all of this already" is a stretch that borders on a complete misrepresentation.
They talked about Cruz's plans for Jihadi immigration, and his feeble attempts to make a show of restricting it. And, the "unfair" Rubio attacks.
Never once did either of them mention the merits of Trump's proposal.
It was pretty much avoided.
.....”Never once did either of them (Cruz or Levin) mention the merits of Trump’s proposal”....
Emotional attachment to a candidate, as deeply as we often see Trumpeters, makes it impossible for them to view anyone in political conversation without it being seen through their starry eyes.