Debating Brain Drain: May Governments Restrict Emigration?

Many of the best and brightest citizens of developing countries choose to emigrate to wealthier societies, taking their skills and educations with them. What do these people owe to their societies of origin? May developing societies legitimately demand that their citizens use their skills to improve life for their fellow citizens? Are these societies ever permitted to prevent their own citizens from emigrating? These questions are increasingly important, as the gap between rich and poor soc...