"America is the world’s unquestioned superpower and a force for good in this world, and we lose credibility on both counts when we choose to lead from behind."
we also lose credibility when we intervene but do so stupidly.
lets look at libya. gaddafi = bad. but not everyone opposed to gaddafi was good, some were pure evil. al qaeda, for instance.
libya has provided more foreign fighters to iraq and afghanistan than any other country. many arrive, become connected to the al qaeda/taliban network, fight some, then return home.
when the revolution kicked off against gaddafi the most effective battlefield commanders had combat experience - gained killing americans in iraq and afghanistan. many of these recieved american support.