Well the US is finally doing it. Not just Muslims this time but everybody. No immigration will be allowed for some time under the guise of COVID-19 protection.

It is spurious. The US already has border controls in place regarding the spread of the coronavirus. For immigrants, it has traditionally required TB scans and other health factors. Adding a coronavirus test would be low cost and a cost that could be placed on the migrant.

As for jobs, work visas already have non-compete provisions put it. Immigrants do not take jobs and this is, indeed, why many advocate for the official migration route rather than unofficial ones.

Instead, this is just part of the America-first rhetoric and the isolationism that is the hallmark of the Trump presidency. And to the world, it is obvious why he is doing it: it works politically. Thus, it is a reflection on the US. The costs are real.

I have a PhD student who accepted an assistant professorship in the US for the Fall above offers from places in other countries. If COVID-19 wasn't enough, there is now very high uncertainty and anxiety. But we will deal with that in an as yet to be worked out way.

That said, if you are a US employer and rely on skilled migrants -- such as in education and the innovation sectors to name two -- it seems to me you are screwed.

Why should anyone who invests in the years to get a PhD risk accepting jobs in the US now and especially if Trump is re-elected in November? The answer is they shouldn't. The US has its advantages but the uncertainty and anxiety, especially to an early-stage career, are too great

As for the rest of the world, if the US is to throw away its leadership in innovation, we need to take the reigns. We need to prepare for the opportunity that another 4-5 years of this at least is here. Double down on hiring. Double down on startups. Double down on innovators.