(The Conversation) — The claim that national security can justify territorial acquisition marks a sharp break from the principles the US championed after World War II. Crucially, these military possibilities have been justified almost exclusively with reference to what Trump’s administration sees as America’s national interests. The existence of this pact did not prevent the German military actions that led to World War II. Previous presidents have perhaps been guilty of paying too little attention to the moral importance of such international principles. This vision, finally, is being undertaken in a world in which the available tools of destruction are even more complex – and more deadly – than those available during the Second World War.