With the emphasis today on the ban the Trump administration has imposed on international students at Harvard, less publicity has been given to the fact that visitors on J-1 visas are an equal part of the ban.
This includes all short term international visitors. Furthermore, the large majority of international Harvard postdocs have been on J-1 visas. (Some who received the PhD in the US are eligible for an H-1 visa but we all know who makes the decision).
This aspect of the ban is almost more shocking than the international student ban (hard to believe I am writing that) given the claimed reasons for the whole thing.
One would be desperately worried about the research consequences of losing so many project workers except that all Federal funding is also being pulled from Harvard.