Sixty years of Western nations excusing and accommodating the lack of freedom in the Middle East did nothing to make us safe—because in the long run, stability cannot be purchased at the expense of liberty. As long as the Middle East remains a place where freedom does not flourish, it will remain a place for stagnation, resentment, and violence for export.
~President George W. Bush, November 6, 2003, in a speech before the National Endowment for Democracy
This quote concisely defines the doctrine of engagement. When in WWII it was the Republican party arguing against aggressive engagement of the foreign powers for evil, it is now the Democrat party which eschews engagement and shuns real projection of power and moral authority.
Moral authority comes not from our own moral rightness. No one is perfect or capable of wielding moral authority based on their own success or ability.
Moral authority comes instead from a general ability on the part of the entity wielding said authority to conform to and support that moral code, as defined by a non-human superior entity, a deity. God. God is the only being capable both of creating, defining, and enforcing a moral code. Moral authority comes from some form of following God’s defined moral rules.
America is not perfect, it is not even mostly perfect. There are many failures. But in todays world, we are the ones striving most for goodness. We are the ones who do not use our power to wrongfully imprison, to destroy, or even to colonize and/or forcefully remove culture. We are the ones who more than any other nation on the face of the earth, stand up to aggressors, protect the downtrodden and weak, and present the case of the forgotten before the rest of the world.
We are America, we are far from good, and our greatness has resultantly slipped. But we strive for that goodness, and we stand against evil.