Is Federalism the Right Approach?

Anthony Fauci has decided that what we really need to do is think about the vaccination rule for domestic travel. So he's talking about it not simply for flying but what, train driving also across state lines? It's domestic flights that he's thinking about but if and when they ever get that, they'll just turn to trains. If and when they got that, they'd just turn to your car. There's no principle here. It's simply, I want this particular outcome and I'll do whatever it takes to get there.