Question for folks not in the USA: has your willingness to travel to the United States changed? Would you attend a conference/meeting/university in the US?
America First means America Isolated.
Also, this isn’t the first time we’ve seen “America first” as a political slogan, and, well, Dr Seuss said it best.
https://jimsmash.blogspot.com/2017/02/america-first-2-dr-seu...
The history of “America First”: https://en.m.wikipedia.org/wiki/America_First_Committee