Michael, I don't think we should reduce this discussion to moral absolutes. There are plenty of things countries can do to encourage/discourage immigration/emigration without impinging upon human rights. Good examples are the things countries do to try and lure their citizens back to their shores. So let's not throw the baby out with the bathwater - I hope we can still have a meaningful discussion of policies that countries might use to influence the flows of people across their borders, and why (from an economic perspective) they might use such policies. I'm going to look for the papers you mentioned about the effect of skilled emigration on the local stock of skilled workers. I'm curious what the econometric strategies will be, since it's tough to prove a counterfactual when you have a nationwide change in policy.