I hate to say this, but we no longer have the luxury of having the ocean of protecting us. It ended when Japan bombed Pearl Harbor..
That much is obvious. But their greater impulse is for the US to “go Canadian”, and just not involve ourselves with foreigners any more, for any reason other than a small amount of balanced trade and a bit of tourism. If we ignore them hard enough, eventually they will ignore us, is their rationale.
Don’t look for rationality or reason in that, and while it isn’t really as xenophobic as it looks, it is just not as xenophilic as is the pestilence that is “internationalism” today.
Up to a point, there is a bit of sense in what they are saying. For example, if Europe wants to ruin itself by recreating royalism, except with gray EU bureaucrats as the “nobles”, and everybody else as peasants, well, no skin off our nose. Likewise, if the Africans in country ‘A’ wish to exterminate the Africans in country ‘B’, our responsibility is little more than to diplomatically deplore the situation.
Granted, they do have some degree of isolationism, seeing no need for the US to import foreigners when we have unemployment here.
Our primary concern should be both to prevent nuclear war, because radioactive isotopes tend to travel great distances; and likewise that no extraordinary contender to world domination arises, at least enough to threaten us.
As long as that happens, we should mind our own business, is the theory.