In the case of Japan or South Korea arming against a more ferocious North Korea or a more aggressive China, it seems clear that there are scenarios in which we would reasonably determine that tolerance of the ills of further proliferation would be justified by the greater good of maintaining our alliances. Santoro’s prescription that we jettison our alliances for the sake of nonproliferation probity is like the Kantian’s who argues that you must not lie even to save your country. But those who are vested with the responsibility of leading our country in an enduringly uncertain and dangerous world cannot be guided by such counsels of perfection. Rather, they should adhere to the old axiom: to hold fast to the central purpose of American statecraft—that of protecting Americans’ security, liberty, and prosperity through moral means—and, in pursuit of that noble aim, to allow every other good to fall where it may.

Elbridge Colby is a Fellow at the Center for a New American Security. Follow him on Twitter: @ElbridgeColby.