Let’s Curb Loose Talk of Using Lower-Yield Nuclear Weapons

Vladimir Putin would not detonate a nuclear weapon if he were winning his war in Ukraine. Using nuclear weapons is a loser’s move. It is an act of desperation.

Which is exactly why the nuclear risks grow as Putin searches for ways to regain momentum in his stalled offensive.

Putin might — as all major Russian military exercises practice and as Russian military doctrine details — use a nuclear weapon first “in response to a large-scale aggression utilizing conventional weapons in situations critical to the national security of the Russian Federation.” The national security of Russia is not threatened by the failure of Russia’s brutal invasion of Ukraine. But Putin’s security is. This might drive him to escalate the conflict through increased bombardment of Ukrainian cities, large-scale cyber attacks, the use of chemical weapons like chlorine gas, or — as I wrote on this site at the beginning of the war — even nuclear weapons.

Russia is now using dual-capable weapons in Ukraine, including the Iskander ballistic missile and, most recently, the hypervelocity Kinzhal cruise missile, that are delivering conventional explosives on cities but could also be fitted with nuclear warheads.

Exploding a nuclear bomb would break a 77-year taboo against using these weapons. There hasn’t even been a mushroom cloud in tests since China exploded the last above-ground nuclear test in 1980 (the United States stopped atmospheric tests in 1962).

“The nuclear taboo is the single most important accomplishment of the nuclear age,” writes Brown University professor Nina Tannenwald, “It is the primary obligation of leaders today to make sure nuclear weapons are never used again.”

Unfortunately, as evidenced in a New York Times article this week, many experts are engaging in cavalier armchair strategies that normalize, or could even encourage, a nuclear war should Putin break this taboo. Former Defense Department official Frank Miller casually suggests responding to Russian nuclear use by firing a “low-yield” nuclear warhead from a submarine “into the wilds of Siberia or at a military base inside Russia.” This would be a signal, he claims, that “this is serious.”

Miller has long championed nuclear use, advocating for developing new, “more usable” nuclear weapons like the low-yield warhead now included as one of the launch options on U.S. nuclear-armed submarines, previously reserved exclusively as a strategic deterrent but now part of the nuclear war-fighting arsenal integrated into conventional war planning over the past decade.

These nuclear war advocates have lost touch with the reality of nuclear war. Even the smallest conceivable nuclear blast would be many times more powerful than the largest conventional bomb. The W76-2 nuclear warhead deployed on one or two of the 20 Trident missiles on U.S. subs has an estimated yield of 5 kilotons, or 5,000 tons of explosive force. That is the equivalent of 10,000,000 pounds of dynamite.

By comparison, a B-52 bomber carries a total of 70,000 pounds of ordnance. The bomber typically carries conventional bombs weighing at most 1,000 pounds. The W76 warhead is equal to 10,000 of these. The largest conventional bomb in the U.S. arsenal is the GBU-43/B Massive Ordinance Air Blast. Nicknamed “the mother of all bombs,” it is a 10-ton bomb, but still just 1/50th the size of the W76.

One of largest conventional explosions ever experienced is the massive ammonia-nitrate blast at a Beirut warehouse in 2020 that experts estimate equaled 200 to 300 tons of explosive force. That is approximately the size of the smallest yield possible with current nuclear weapons, like the air-dropped B61-12. But a nuclear explosion would be much more destructive as the heat from the blast would set off uncontrollable mega-fires and its radiation would kill or injure thousands.

The destructive power of nuclear weapons is so horrific that using even a “small” nuclear weapon would still be the largest single combat explosion since the end of World War II. This is true of the W76 (one-third the size of the Hiroshima bomb) as well as the lowest setting for the B61 (1/50^th the size of the Hiroshima bomb). Whatever “signal” nuclear use is intended to send would be lost in the horror of the consequences, even assuming that all the actors in this nuclear drama are rational, which is far from clear.

“There is way too much loose talk about using nuclear weapons,” Tannenwald told me. “We need more discussion of the dangers of breaking the nuclear taboo.” Not just first use, but second use. “We wouldn’t respond to the use of chemical weapons by using chemical weapons ourselves,” she argues. The same must be true for nuclear weapons.

Any use, anywhere, for any reason not only encourages the use of these weapons by other nations, but it carries the very real risk of escalation into a global thermonuclear war. While some believe “we have to match every rung on the escalatory ladder,” warns Tannenwald, “using a nuclear weapon first or responding with a nuclear weapon of our own just invites further nuclear escalation.” There is no logical termination point once the taboo is broken.

What do we do to lower the risks? “Assemble the elders,” says Tannenwald, meaning that we need experienced, senior leaders to reinforce the barriers to any nuclear use. She cites the testimony of former Secretary of Defense James Mattis. “I do not think there is any such thing as a tactical nuclear weapon,” he told Congress in 2018, “Any nuclear weapon use any time is a strategic game changer.”

Having senior validators speak publicly and clearly about the dangers could encourage President Joe Biden to declare that the United States and NATO have no intention of using a nuclear weapon first in this conflict, as former White House official Jon Wolfsthal recommends,  thereby strengthening the norm against use.

In the longer term, we must change our attitude toward these weapons, understanding that nuclear weapons are not our greatest strength but our greatest weakness. “The U.S. nuclear arsenal does nothing for us in this conflict. It did not keep Mr. Putin out of Ukraine,” writes Ploughshares Fund Policy Director Tom Collina. “Because he is willing to use the threat of nuclear war to deter intervention in Ukraine, the existence of nuclear weapons, if anything, helped enable him.”

We need a chorus of wiser voices to still the cries of the nuclear warriors and calm journalistic nuclear voyeurism. Former officials could have their statements join calls from anti-nuclear activists, advocates for restraint, and all those who understand that any nuclear use is unnecessary, immoral, and unacceptable. We must hold this line.

This article originally appeared in Responsible Statecraft.