Something to keep in perspective: Yes, there is a significant amount of illegal immigrants crossing the border, and this is a problem, but if it is true that the number of illegal immigrants is about 1 million people, and if 80% are not vaccinated, then that is the potential for 800,000 people now in this country that can spread the virus.
But when you compare that to the adult population of the United States (~253 million) and the fact that 30% are still not vaccinated, that means we are currently sitting on about 76 million unvaccinated Americans (in addition to the children who cannot currently take the vaccine). So I see a problem that is almost 100 times worse than the border issue (with regards to Covid).
I say let's get our crap together first on the big problem, and then deal with the smaller problems thereafter.