If you look at their ratings of Congresscritters, you can see that good ratings on immigration correlate strongly with conservative positions on other issues. Demonrats are almost entirely weak on immigration.
No one should be elected POTUS who is weak on this issue, because continued Third World immigration (now running at roughly a million a year) is going to transform the U.S. into a socialist country very quickly. It has already made Calif. a safe state for the Left.
If I remember correctly, the last Census showed that 1/6 of the US population is Hispanic.