The Federation of American Scientists announced on January 29th that the new W76-2 low yield nuclear warhead has been deployed. This is a low yield variant of a warhead traditionally carried on the Trident missile. The Pentagon confirmed on February 4th that this warhead was requested, designed, and produced under the Trump administration. Undersecretary of Defense, John Rood, claimed that the benefits from this weapon, “strengthens deterrence and provides the United States a prompt, more survivable low-yield strategic weapon; supports our commitment to extended deterrence; and demonstrates to potential adversaries that there is no advantage to limited nuclear employment because the United States can credibly and decisively respond to any threat scenario” (Defense News).
The W76-2 warhead has been deployed on the USS Tennessee (SSBN-734), which already has the capacity to fire high yield nuclear weapons. This is cause for major concern as if any of the weapons are fired, it is likely that the adversary will assume the high yield has been fired, and will respond with a high yield weapon of their own. Supporters of the low yield system, however, believe that this will be a strong effort towards deterrence of Russian nuclear weapons. US defense officials believe that Moscow would use low yield nuclear weapons to prevent the US from entering or extending conflict under the “escalate to de escalate” doctrine. Due to the fact that the US only had high yield weapons previously, the thinking goes that the US would hesitate to use it.
This raises further concerns about rationalizing the use of nuclear weapons in a conventional setting. The low yield nuclear weapons were designed to carry a smaller payload than the one detonated in Hiroshima, Japan during World War II. Due to the smaller explosive power of these weapons, it would be far easier for a country to rationalize using it against a conventional adversary. The blowback from this could be devastating as it would be the first time a nuclear weapon has been used since World War II. If a country can rationalize the use of low yield nuclear weapons against conventional adversaries, it then becomes a slippery slope that could lead to all out nuclear warfare.
Low yield nuclear weapons may help promote deterrence in the short run, however, it is likely to heighten tensions between nuclear powers. The idea that low yield weapons could possibly be used in a conventional setting is frankly quite startling and could spell disaster during war time or in times of peace. These weapons could also bring about a new nuclear arms race. Instead of racing for the biggest, baddest nuclear weapons, the race could now be for a nuclear weapon with the lowest yield. The W76-2 has a blast yield of around 100 kiltons(kt) which is almost ten times the yield of the weapon dropped on Hiroshima. It is startling to think that this weapon could be considered low yield, and even more startling to think that a weapon like this could potentially be used in a conventional setting.