Let's say you apply for a faculty position at a good public university. In physics, it would not be uncommon for there to be around 200 applicants. Imagine th

Let's say you apply for a faculty position at a good public university. In physics, it would not be uncommon for there to be around 200 applicants. Imagine that only say 50 of them are great...Teaching positions are also competitive. That's one level. Now, the US is in an enviable position of being able to skim top people from around the world who come here to study--so we end up with a huge competition for a small pool of positions. The notion being that all other things being equal, having a large candidate pool is more likely to result in stronger candidates. That's what we risk giving up by limiting immigration--especially after we (I am from the US) train people here to do research.