If Isolationism is:
Controlling the borders, then I'm all for it.
Sending the invading illegals home, then I'm all for it.
Telling Europe to defend themselves since they don't like us, then I'm all for it.
Drilling our own oil, then I'm all for it.
Digging our own coal, then I'm all for it.
Letting the barbaric primitive places of the world fend for themselves, then I'm all for it, so long as the other nations keep their militaries out of those areas as well.
Isolationism can be a good thing. Just think of all the Americans that could have been saved if Wilson had let Europe fight it's own wars, and if LBJ had left Vietnam alone.
So long as the United States retains the strength to turn the rest of the planet into a glazed donut, and otherwise be able to protect our freedoms, the rest of the world can and should go to hell without us.