A “just war” in Ukraine would be a catastrophe for all parties. But a “just peace” framework that recognizes the root causes of the conflict can bring the U.S., Russia and Ukraine to a mutually beneficial outcome.

Just war principles do not require Western nations to practice pacifism or ignore Russian aggression in Ukraine. But they may still guide nations to a nonviolent resolution, and Pope Francis can help.

Vladimir Putin‘s aggression against Ukraine fails just war theory, but the ethicist John Davenport writes that NATO forces are morally justified in responding with proportionate military action.