MICKEY KAUS: Does President-Elect Trump understand that the immigration issue is at the heart of his election? “The Trump supporters who voted on the issue not only reflect majority support for most of his policies, but they tend to care about the issue intensely. If Trump backs down on the clear policies in his big August 31 immigration speech, . . . he will dissolve this base of support. Since he has no other big base of support — not the Democrats who hate him, not established Republicans, who may hate him even more — he’ll be Wile E. Coyote in mid-air, with nothing under him.”