The reason, Hyten said, is that the United States needs a greater amount of variety in the low-yield weapons available in the nuclear arsenal.
Russia is developing or has built 11 delivery platforms capable of launching low-yield nukes — though that number may actually be higher, as Hyten specified those were only the systems he could talk about in an unclassified setting.
Meanwhile, the United States can only fire a low-yield nuke from aircraft, he said. The B-2 and a number of fighter jets are able to drop low-yield B61 gravity bombs on targets, and the B-52 can launch a nuclear cruise missile from standoff distances.
But while the United States can position its bomber force to respond to tactical nuclear threats, those aircraft would have to fight through a denied environment to drop low-yield assets.
As the Defense Department worked through war games detailing how the United States could respond to a battle with Russia, “we felt strongly that we needed another delivery option,” Hyten said.
Reif and other nonproliferation experts, however, have echoed Reed’s concerns that a low-yield SLBM could lead to escalation in a potential conflict with Russia.
“Given that U.S. strategic submarines currently carry SLBMs armed with higher-yield warheads, how would Russia know (or discriminate) that an incoming missile armed with a low-yield warhead wasn’t actually armed with high-yield warheads?” Reif said.
“How would it know that such limited use would not be the leading edge of a massive attack, especially if the targets would not be battlefield targets but targets of high-value to the Russian leadership? The answer is that Russia wouldn’t know.”
Reif also said that a submarine’s position would likely become known to adversaries once it fires a ballistic missile of any yield, which could undermine one of the key strengths of ballistic missile submarines — its survivability.
When lawmakers presented that same concern, Hyten said he could not address it in an unclassified setting.
The Pentagon plans to spend $48.5 million over the next five years to develop the low-yield SLBM warhead, according to documents provided to Defense News.
Even if the department is permitted to move forward with its plan to develop a new low-yield warhead, the number of SLBMs would stay the same, Hyten stressed. The department plans to remove some of the W76 warheads off the existing SLBMs and affix the low-yield warheads. The number of missiles that will be converted to the low-yield variant is classified.