Though it's tempting to attribute the Long Peace to nuclear deterrence, non-nuclear developed states have stopped fighting each other as well.

WSJ: Steven Pinker: Why Violence Is Vanishing

However, the Nuclear Triad has been integrated with non-nuclear strategic capabilities, which strengthen the credibility of U.S. offensive deterrence and form the New Triad.

CENTERFORSECURITYPOLICY: US Nuclear Stockpile

Likewise, the administration's declaration that it would not unleash nukes on non-weapons states that lived by the rules of the Nuclear Non-Proliferation Treaty (NPT) was criticised either for being unwise (because it curtailed deterrence against biological and chemical weapons), or misleading (because it is so full of loopholes that it does not curtail deterrence much at all).

ECONOMIST: Nuclear diplomacy: Chain reaction | The