He who controls his borders is "The Decider."

[moondust]

Not to be overlooked is the fact that once you have control of your borders you can, at least in theory, DECIDE who will be the new immigrants. They may be from just across the border or just across the pond or just across the universe. They may be the hapless victims of impoverished nations or individuals with special circumstances or the targets of genocide. There is no longer any good reason that the accident of geographic proximity should be the determining factor in who immigrates to the U.S. and who does not.

[acmejack]

1. More importantly you control who may emigrate!

There was a time when the Stasi routinely machine gunned down would be escapees from East Berlin as they tried to flee to freedom. We may discover all too soon that WE are the ones on the wrong side of this damnable wall.

[moondust]

2. As long as there are channels open

that will allow anybody who is denied exit from the U.S. to publicize their case, i.e. a largely unregulated Internet and/or a few honest media outlets, I doubt that is a serious threat.

I know about Berlin. I lived there for a year and a half in the 70s and indeed saw no-man's land up close.