Force is always only the form love takes against terrible evil in the last resort when nothing else will protect the innocent, restore justice, and bring about the conditions for peace. The old Chestertonian nugget remains: “The true soldier fights not because he hates what is in front of him, but because he loves what is behind him.”

St. Thomas Aquinas knew more than his modern emendators do about grounding his just war deliberations—and much else—in the cardinal moral virtue of prudence.