"I can just imagine a young Tesla trying to immigrate here today.. the professional associations and protectionists would try to stop him."
---
I fear they already have...:
http://www.freerepublic.com/focus/news/1237232/posts?q=1&&page=190#190
I think many have different views of what they want for America.
I see America as a commercial state, where even a poor person can become rich. And where people from around the world who believe in liberty can come. The only limitations I would seek for immigration are to make sure it isn't enough to destabilize the nation. So many more then we are letting in legally now.
I also see America as revolutionary in nature. Where we don't stop new technologies.. even if they would mean millions losing their jobs. So scientists from around the world, who get held down by their nation's bureaucracies, special interests, eco-nazis or whoever.. can come to America and pursue their dreams.