Chuck has an answer for the porous borders with which I agree. Don’t expect it to be implemented, though. America wasn’t THAT isolationist before WWI or WWII. But I think it would work.

Except for one thing. The limitations on the ownership of houses would have to be expanded. I don’t think that, despite the racial implications, anyone who is a first or second generation American could own one. There are people in my church who think that it is terrible that we don’t want illegal immigrants here. It is because they are legal immigrants but their relatives are not. So, you’d have to limit it to folks who have been here a while. And folks who have blended in rather than keeping their family’s cultural heritage.