Reply #25: It's part of the "isolationist" mentality and not a strict physical reality

[YOY]

Frankly, those Oceans have stopped protecting us from easy destruction the moment the airplane was put into military use (or perhaps the moment the first intercontinenal missle was perfected.)

but in the case of a prolonged war, more or less it still took the British significan financial and human power to reach North American in both the Revolutionary War and War of 1812.