The United States could substantially cut its defense budget and still spend more money on our military than every country that even plausibly threatens us combined. Can someone explain why that isn't enough?
There is one explanation. If you're someone like Bill Kristol, who wants to maintain American troops in countries all over the globe forever, favors military intervention in countries like Libya that pose no threat to us, is ideologically committed to remaking more foreign countries via force, and favors ratcheting up the likelihood of military confrontation with countries like Iran and China, current levels of "defense" spending makes perfect sense. Imperial garrisons are expensive to maintain, after all, and more foreign wars will be costly to wage.