Or perhaps it would be more accurate to describe the problem as one of wild swings in US domestic politics between excessive isolationism and excessive foreign intervention in response to short-term events, and untempered by any longer-term historical perspective. These days, after a decade of war in Iraq and Afghanistan at an estimated cost of $4 trillion (including the medical care that veterans will need for the rest of their lives), the pendulum has apparently swung back in the direction of isolationism.