[ericd]

I don't understand the motivation there at all - shouldn't the US be trying to hold on to the most educated foreigners as much as possible?

[ufo]

You made the mistake of assuming that the US immigration policy is rational.

[jonemo]

I used to ask that question and have been told that the US greatly benefits from having US-educated people in positions of power around the world. I don't know if this is true, but what is true that a surprising number of heads of states of countries that are considered political allies of the US have degrees from US universities. I first noticed this trend when reading about Pacific island nations.

[ericd]

I suppose, but the number of people leaving the country that that requires is fairly small, unless you're talking about spreading a cultural hegemony. I think it's likely just irrational.

[anusinha]

One country that does it right is Canada--they try very hard to keep top talent in the country instead of going to their previous homes.