None. They encourage only skilled immigrants. That should be Our policy here. There is no such thing as too many skilled workers. I just came back from visiting many countries in SE Asia and was impressed how strict they all are in controlling their borders. Singapore was exceptionally strict. But they do encourage foreign workers who are needed in various skill levels. Those workers are given work permits for a definite period of time. Only the highly skilled such as doctors and engineers are encouraged to stay permanently.
So what is your point?
Going on and on about foreign countries that have nothing to do with us, and that are so strict that they can forbid chewing gum to the people they rule, what does that have to do with anything related to the GOP primary?