From the part of the show I listened to, Rush theorized that Trump is pushing this amnesty deal knowing it would be rejected by the Democrats, which it already has out of hand, after which Trump can say: "look, I offered to meet you half way" and that Trump was being generous but that the Democrats nonetheless threw a temper tantrum, and the Democrats can't stand meritocracy.

Rush made other points, but this seems to be his main one.