As we defend the peace, we also have an historic opportunity to preserve the peace. We have our best chance since the rise of the nation state in the 17th century to build a world where the great powers compete in peace instead of prepare for war. The history of the last century, in particular, was dominated by a series of destructive national rivalries that left battlefields and graveyards across the Earth. Germany fought France, the Axis fought the Allies, and then the East fought the West, in proxy wars and tense standoffs, against a backdrop of nuclear Armageddon.