A segment of his voters might conclude that he wasn’t at all serious about illegal immigration -- and, for that matter, that he isn’t a great dealmaker and doesn’t tell it like it is, two other traits that distinguished him from career politicians in their eyes. The polls, most of the talking heads he watches and probably his relatives are all telling him he is doing something smart on immigration. He might be making a big mistake.
There is no question that any deal on DACA or any amnesty of any kind for any illegal alien, is a big mistake.

Most Americans don't want to wallow in the weeds of this issue, they want a government that does its job and enforces US immigration law even when it's "hard" or unpleasant.