A couple of more items to add to the conversation. A recent David Brooks piece invoked Niebuhr. Adam Serwer offers a counterpoint: What Would Niebuhr Do?
An NPR interview with Sean Casey, Professor of Ethics at Wesley Theological Seminary in Washington, DC on the question whether the intervention in Libya is just.
Preaching Grace on the Square 
Unfortunately, both Serwer and Casey offer pretty thin gruel when it comes to discussing the problems connected with intervening in Libya. President Obama has carefully avoided self-righteousness in his language about the current actions but it would be helpful to hear a more thorough examination of the just war theory to this particular case. Thanks for raising the issue.