Ross tackles just war theory:
My own view, though, is that just war theory has always been in crisis, and that modernity has only heightened the contradictions - because almost all of the standards the theory sets are so malleable in practice, and so difficult to apply consistently to the complexity of war and statecraft. Consider the Catechism's definition: Who gets to define what sort of harm is "lasting, grave, and certain" enough to justify going to war? Who decides when all means of preventing conflict "have been shown to be impractical or ineffective"? Doesn't almost everybody enter a war convinced they have "serious prospects of success"? ...
This doesn't make the theory useless by any stretch, but it's useful primarily because it provides a broad framework of restraint: If you're thinking about questions of justice, you're less likely to commit an injustice, even if no perfect consensus exists on the distinction between a licit campaign and an illicit one.
And if you need to win an election ... ?