You must have a perverted definition of isolationism.
“A policy of non-participation in international economic and political relations.”
It used to be that a couple of oceans and the Monroe Doctrine would keep them from our shores. But they couldn’t, they can’t, and they won’t leave us alone. Even President Grant had to act to keep the French out of Mexico and off our border.
Right now, China is building a deep water port in the Caribbean, it controls both sides of the Panama Canal, and is wheeling and dealing with every tin horn South American El Supremo they can.
They figure that by attacking and destroying Bremerton and San Diego, by some means, they will have neutralized the US Pacific fleet. And they are very clear about having to “distract” America with a disaster to do so as well. They want the Pacific to be their ocean, not ours.
Yeah, go hide somewhere and ignore the world, full, as it is, of murderous scoundrels, pirates, dictators, conquerors, fanatics and criminals. But don’t expect them to do the same. Ever.