Stratfor's Robert Kaplan has an excellent
article for
RealClearWorld on the extent to which world peace is an artifact of U.S. military oversight. See his conclusion:
Great powers are rarely appreciated in their own time, for the benevolent order they spread goes unacknowledged by those who benefit most from what they provide. Global civilization -- and the system of legal norms that arises from it -- survives to a significant extent because the American military remains robust and widely deployed. And that, in turn, is not a situation that is necessarily permanent, or one that can ever be taken for granted.
Particularly since isolationism is the flavor of the week in the U.S.