Isolationism
The isolationism that was the goal of most of our Founding Fathers, although an appealing idea, was a lot easier to carry off back when it took weeks to get across the Atlantic in a wooden sailing ship.
I shudder to think what would have happened if we had been solidly isolationist throughout WWII. One thing for sure: Europe and Asia would now be very "stable." And for some foreign policy types, that's the only goal.