First there’s what Glenn Reynolds wrote and he would know:

The GOP establishment has an almost-religious attachment to open immigration. It appears to be their only firm principle. It’s what led to Trump’s rise.

And then there are the three top rated comments. First:

“It appears to be their only firm principle.”
GOP principles:
1. Have contempt for conservative voters.
2. Go after conservative members of Congress ruthlessly, but treat Democrats with respect.
3. Do whatever it takes to win the love of the main stream media.
4. Always believe in more government.
5. Immigration, immigration, immigration.

Second:

Get replaced by a foreigner brought in to do your job and see how you feel. You expect people to vote to give their jobs to cheaper immigrants?

And third:

I dislike Trump, and I distrust whatever his politics are. That said, I believe him on the immigration issue, which as we are seeing in Europe, is existential.

That’s it. Says it all. The party of closed borders will win the election but if it weren’t for Trump, no such party would exist.