As the conditions for excellent research improve in many countries around the world, it is unavoidable that more and more U.S.-trained researchers will spend at least part of their careers abroad. This is not my big concern. Scientific research is not a zero-sum enterprise, where one country's gain is another's loss. Uncertain funding in the U.S. and impediments to open collaboration — like restrictions on immigration and visas or even social biases against foreigners — may increase incentives for researchers to go abroad; more importantly, those conditions, and anything else that makes scientific collaboration less easy, harms America.
The bottom line: It is not the flow of American scientists abroad that concerns me. It is the discouragement of the free flow of researchers in and out of our country — Americans and non-Americans.
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