If Republicans don't run on immigration they will lose and deserve to lose. That's what got Trump into the rainbow house and what will get him tossed out if there's no serious action on the immigration front by 2020.
Trump is there to channel the discontent and prevent it from getting out of their control. If there's been any actual improvement in the jobs/economy front it's just more placation in the hope people will forgive his broken promises on immigration.
If you're White they want you "diversified" out of existence not just divided. The easiest way to keep people divided is to have a country full of different races.
The entire US is comped. That's not even debatable anymore.