...in a European Populist way, making it the main issue for some candidates (not the pseudo hispanics) and opposing it in a radical way?
Explain with maps.
And it has not happened long before Trump? I thought it had.
Now, of course, to the extent Trump makes it even more associated with the Republican party, it is a great gift for the Dems. Remember, US has FPTP a two-party system. Getting 40% of the vote is not enough to win elections. Both parties have to be grand coalitions, which means radicalism - in any dimension - is damaging. Limiting partisan base to just whites and desperately losing cities has already been a problem for the Republicans. The more openly anti-migrant speech will force minorities and urbanites even further into the Dem column.