Defense Secretary Ash Carter, as he comes into what could be his last year overseeing the most powerful military on Earth, has begun talking about something surprising: a return to great power competition. During a recent interview at the Pentagon, we asked Carter how he thought about navigating this new world, and he returned over and over to the same answer: deterrence.
But as the norms and tools of warfare are changing, how well does deterrence still work? Can this Cold War–era idea still keep the peace in a new era? Here's why this challenge has such high stakes for the world — and what Carter had to say about it:
