my understanding is post docs are virtually all on J1 visas, which is a meaningful part of uni hiring

> used to be

So... Now those spots will have to go to American students and grads?

Some will.

Most won't be filled at all.

+1 This will also reduce demand for these programs from international students - make tuition more expensive for locals. Asking to consider 2nd/3rd order effect seems like a bit too much for a median hn poster though