The U.S. Defense Department on Tuesday confirmed earlier reports that the Navy has deployed a submarine armed with a newly developed and controversial low-yield nuclear weapon, the W76-2.
The Federation of American Scientists first reported last week that the five-kiloton W76-2 deployed aboard the USS Tennessee ballistic missile submarine, which left Kings Bay Submarine Base in Georgia in late December.
The low-yield W76-2 is a modified version of the 90-kiloton W76-1, a warhead that can be carried by the Trident submarine-launched ballistic missile.
The Department of Defense requested modified, low-yield sub-launched nuclear ballistic warheads in a 2018 review that concluded Russia’s development of similar “tactical nukes” required a deterring counterpart.
Proponents of the move argue that if Russia detonated a low-yield tactical nuclear weapon in a conflict situation, the U.S. may hesitate or refuse to respond because most of Washington’s own nuclear weapons are orders of magnitude larger.
The rapid development of low-yield nuclear warheads may deter Russia’s willingness to use their own, supporters say, and allow the U.S. to respond proportionally.
“This supplemental capability strengthens deterrence and provides the United States a prompt, more survivable low-yield strategic weapon,” Undersecretary of Defense John Rood said in a statement.
Rood also said the deployment “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.”
The Federation for American Scientists critiqued the strategic reasoning behind the W76-2.
“While Russian low-yield nuclear weapons lower the threshold making nuclear use more likely, U.S. low-yield weapons instead ‘raise the nuclear threshold’ and make nuclear use less likely,” Hans Kristensen, the director of the FAS’s nuclear information project, and William Arkin, a journalist and consultant to organization, wrote last week.
“All of this sounds like good old-fashioned Cold War warfighting.”
The FAS estimates that the U.S. now possesses about 50 W76-2 warheads in addition to about 1,000 other low-yield nuclear weapons, which can be delivered by aircraft. Submarine-launched ballistic missiles are considered more likely to penetrate sophisticated air defenses.