If they are fed up with immigration they are stupid. “Gee we have declining birth rates and we want to deny this pool of labor that might correct course because they are brown.” The american empire was built on easy immigration. Turns out the tired and poor that we took in can build empires and win europe’s major wars for them.
Immigration is a duct tape solution to fixing things at this point. It is not going to build you an empire today.
Why aren’t Japan, Korea, China importing millions from India and Africa to replace their falling birth rates? Because people are not identical interchangeable units.
If you drop 1 million Africans into London they don’t simply become British, they are just Africans living in London. People understand intuitively that replacing the native population with foreigners at massive scale mostly just erases the native culture and people (which have existed for thousands of years).
The American Empire was built by specifically importing millions of Europeans who shared much history and culture (religion, appearance, history). If America had instead been grown by importing people from India or Africa, the American Empire would not exist.
The job market has imploded and the economy hasn't been growing since 2008. There definitely needs to be a cap.