Co60

I'm aware of the positive economic impact that comes with the free movement of labor, but recently the push back I have seen on this topic has shifted from "they are taking our jobs"/overstating Borjas' conclusions to "the terrorists will flood in and murder us all".

Being ignorant on the literature related to immigration and national security, I was curious if there has been any studies or attempts to quantify if this is a real issue or just peoples' xenophonic intuition. My assumption is the latter but I frankly don't have anything to back up that thought at the moment.

What is the current thought on non-compete contracts (specifically in the US)? Are they nessecary to protect business investments, or do they cause more harm than good by artificially restricting the pool of qualified labor? I understand a non-compete can include many different aspects (from keeping employees from leaving and taking contacts, to protecting trade secrets), are some elements of these contracts more justified than others?