It's taken a long time for Germany and Japan to recover from the Second World War. After enduring the indignity of military occupation, they regained sovereignty only by guaranteeing against future threats to peace. Germany's new constitution only authorized military force in self-defense or in collaboration with collective security agreements. Japan's Article Nine went further, "forever renounc[ing] ... the threat or use of force as a means of settling international disputes." But this post-war settlement is unraveling before our eyes. The Obama administration must learn to distinguish the urgent from the truly fundamental. Unless it rethinks our traditional post-war partnerships, it risks an authoritarian Japan and a profoundly alienated Germany -- destroying one of the greatest legacies of the twentieth century.