The President’s recently-released Nuclear Posture Review (NPR) has come under intense criticism for its revision of the U.S.’s declaratory policy, the statement that sets out when the U.S. would consider employing nuclear weapons. Declaratory policy has two purposes. Publicly, it’s a warning. Privately, it provides the military guidance for building and modernizing the U.S. force, and so ensures the U.S.’s weapons are actually useable in a crisis. In other words, it makes deterrence creditable, politically and militarily.

The new NPR goes into considerable, lawyer-like detail about what the U.S. might do in particular circumstances after it was attacked. But it forgets that the basic duty of the U.S. Government – and the basic purpose of the U.S. nuclear arsenal – is not to respond to attacks. It is to prevent them from happening in the first place. The NPR, by focusing only on retaliation, neglects this fundamental duty. It return the U.S. – for all the President’s claims to be making a bold new stride towards a world without nuclear weapons – to the Eisenhower-era emphasis on ‘massive retaliation,’ though in the context of a far smaller U.S. arsenal.

The lawyer-like language of the NPR has perils of its own. The Obama Administration appears to feel guilty about the fact that the U.S. is a nuclear state, and to believe that it can propitiate this guilt by being as exact as possible about U.S. policy, just as children with a guilty conscience over-explain their actions to their parents. But the purpose of declaratory policy isn’t to spell out scenarios. The public face of a good declaratory policy should be short and obscure. Its purpose is to create doubt, and therefore deterrence, in the minds of adversaries.

The NPR’s declaration that the U.S. will not use nuclear weapons in response to an attack by a non-nuclear country on the U.S. with chemical or biological weapons is far too exact. All it does is broadcast that the U.S. is willing to be hit by some WMDs without replying in kind. That does nothing for deterrence. Instead of making the use of nuclear weapons less likely, the NPR, by weakening deterrence, makes this more likely.

The U.S. public isn’t eager to use nuclear weapons. But it knows that a strong U.S. is the best guarantee of peace, and that, as Jack Bauer would be the first to point out, biological weapons pose immense dangers of their own. That’s why, according to a new Rasmussen poll, “just 25% of voters agree with the president’s decision to rule out a nuclear response if a non-nuclear country attacks America with chemical or biological weapons.”