In fact, the idea that the United States should always try to "lead" is completely bone-headed."Exerting leadership" is not the central objective of foreign policy; it is a means to an end but not an end in itself. The central purpose of foreign policy is to maximize the nation's security and well-being. If exerting "leadership" contributes to these ends, fine, but there will be many occasions when the smart strategy is to hold back and pass the buck to someone else. Blindly declaring that the United States must always go to enormous lengths to lead, and must constantly strive to reassure allies who need us far more than we need them, is mere jingoistic hubris. It's an applause line, but not a strategy.
A good, succinct explanation of not just why Republicans are wrong, but also many liberal interventionists.