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Stale Thinking on Tac Nukes Reheated

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Quote of the week:

“Neither a viable posture nor a viable doctrine exist … for the employment of tactical nuclear weapons.”
—William R. Van Cleave and S.T. Cohen, Tactical Nuclear Weapons (1978)

As the confrontation with North Korea builds, there is growing sentiment within South Korea to reintroduce U.S. tactical nuclear weapons withdrawn when the Cold War ended. Concurrently, there is another boomlet in Washington for new tactical nuclear weapons in the run up to the Trump Administration’s nuclear posture review. Both ideas are unwise and deserve once again to be rejected.

The quote from Van Cleave’s and Cohen’s book was a lament as well as an acknowledgement of reality. They wanted the U.S. Army to take tactical nuclear weapons more seriously, but after going overboard in the 1950s and 1960s, the Army leadership increasingly held the view that they were more of a hindrance than a help in fighting ground campaigns. After the Cold War ended, the Army rid itself of the nuclear mission and hasn’t looked back. If tac nukes are to be used in a war on the Korean Peninsula, the Air Force will do the deed.

Van Cleave’s influence was never greater than during the first Reagan Administration, where he served as an advisor. For the most part, however, he defended nuclear orthodoxy and mentored from university perches. Cohen is perhaps best known as the “father” of the “neutron bomb” (or “enhanced radiation weapon”), designed to maximize radiation while limiting blast effects when used on battlefields or urban areas.

The neutron bomb made good sense to Secretary of Defense James Schlesinger and other nuclear strategists as a way to counter Soviet tank armies advancing across Europe. But it didn’t make sense to many in Europe who declined to be defended by enhanced radiation weapons. The neutron bomb was easily caricatured by the anti-capitalist Left as a weapon to kill people rather than damage property. President Jimmy Carter didn’t need much convincing to walk away from the neutron bomb, which he viewed as an unwanted inheritance from the Ford Administration.

Both Van Cleave and Cohen are no longer with us, but their views haven’t died. Supporters of a new tactical nuclear warhead design advance two arguments: First, there is a tactical nuclear weapons “gap” with Russia and, second, the Pentagon needs to modernize a Cold War-oriented stockpile to meet post-Cold War threats like that from North Korea. There is a sotto voce argument, as well: the designers of the Cold War stockpile are retiring or retired, and their younger replacements need to cut their teeth on a new design.

The arguments for adding another low-yield warhead design to the current U.S. stockpile don’t add up. The stockpile already includes three warhead types whose yields can be dialed way down or up. To deal with post-Cold War threats, advocates argue that small mushroom clouds are better than big mushroom clouds. They also believe it is important to have rungs for escalation and escalation control in nuclear exchanges. But if large mushroom clouds are insufficient as a deterrent, small mushroom clouds are unlikely to be more persuasive.

The fixation with tactical nuclear weapons reached its apogee in the 1950s and 1960s, epitomized by Herman Kahn’s tome, On Escalation: Metaphors and Scenarios. Published in 1965, Kahn suggested a notional escalation ladder of no fewer than forty-four rungs. In Kahn’s fertile mind, signaling escalation and escalation control was akin to buying a new Studebaker from the dealer and haggling over the price. I’ll see your five kilotons and raise you ten. Your move.

To give Kahn his due, he recognized that:

“All bargaining, at the upper as well as lower rungs of the escalation ladder, is bound to be complicated by the fact that each side’s information would be different; each side might be attempting to bluff the other side, to give misleading information; there would be communication difficulties; there would be the pressure of time; there would be a play to emotions, irrationality, anger, miscalculation, bad doctrine, misapprehension, mistake, and shock.”

Even so, these complications could be tamed, in Kahn’s view, by analytical rigor, just like like his rungs up the escalation ladder. Kahn’s confidence never wavered. For him, the problem of the “fog of war” was subject to “systematic overestimation.” Here, he employed the analogy of a ship’s captain who could chart a course through a blinding fog:

“One of the greatest misconceptions current in discussions of command and control is a failure to understand how well a central war might be run, at least initially, by ‘dead reckoning.’

“The commander or decision-maker may know a good deal about how the war started and the basic conditions existing at the outbreak … From this point forward, even though he is completely cut off from all information external to his own organization and forces, and perhaps even from much of that, he may still have enough of an idea of events and their timetable, at least in outline, and a sufficient judgment of what the other side is trying to accomplish (through knowledge of its logistics, forces, doctrine, and other constraints) to ‘play’ both sides hypothetically by dead reckoning – adding and correcting with whatever information comes in.”

Kahn clearly went overboard here and elsewhere. The more detailed speculation he provided, the more obvious it became that, despite his brilliance, he lacked basic common sense. Deterrence strategists who avoided detail were on firmer ground, but they, too, avoided the central question of how a nuclear war ends. If two states have screwed up so badly that they have used nuclear weapons on a battlefield, how are they supposed to agree on numbers and yields?

Today’s situational awareness may be well beyond even Kahn’s imagining. But the sensors that provide situational awareness could also be messed up once the nuclear threshold is crossed. The basic assumptions behind the use of limited nuclear options remain breathtakingly facile. It’s folly to assume that nuclear exchanges can be tidy and that nuclear weapons can be domesticated by downsizing yields. Or that command and control can be maintained on a nuclear battlefield. The dominant impulse once the balloon goes up will most likely be to speed up, rather than slow down decision making. Until advocates of limited options for the battlefield use of tactical nuclear weapons and new warhead designs can explain to us how this war ends, they cannot make a sound case.

Still, tactical nuclear weapons haven’t gone away. They have become crutches for weak states to deter stronger ones. If the weaker state crosses the nuclear threshold first to make it harder for the stronger state to advance, does it make sense for the stronger state to compound difficulties for its ground operations by retaliating in kind?

The United States, which enjoys conventional military superiority, powerful allies, and possesses a few thousand operational nuclear weapons with widely varying yields, doesn’t need to match up against an adversary’s tac nukes. Instead of fighting fire with fire, the Pentagon can fight fire with very high-pressure water hoses. Put differently, the way to beat tactical nuclear weapons is with overwhelming conventional and air power. There are no targets for small mushroom clouds that conventional capabilities can’t handle. And if conventional firepower isn’t effective enough, then small mushroom clouds won’t help, either.

Nuclear soothsayers tell us that it’s not about battlefield use; it’s all about deterrence. But the point of deterrence is no mushroom clouds, not tailor-made, low-yield mushroom clouds for escalation control and battle management. Protecting allies with the neutron bomb was a bad idea in the 1970s; protecting them in the 2020s with a new tactical warhead design is also a bad idea.

Even with expensive bells and whistles, deterrence has already failed twice between nuclear-armed states that fought limited wars over contested borders — China and the Soviet Union in 1969 and India and Pakistan in 1999. These wars ended in draws, as did the Korean War. A second war on the Korean Peninsula would result in U.S. victory, but if North Korea isn’t asleep at the switch, victory will almost certainly come at high cost. The re-introduction of tactical nuclear weapons that George H.W. Bush removed from South Korea won’t change this bottom line.

When it comes to capabilities for nuclear warfare, better is the enemy of good enough. Bells and whistles are not just expensive, they might also require the resumption of nuclear testing by the United States — and by Russia, China, India and Pakistan. Depending on who goes first, the progression of resumed testing might vary, but the results would be equally catastrophic to the nuclear safety net woven patiently by earlier generations. Giving a rising generation of laboratory scientists practice in designing a new warhead isn’t worth these costs.

As for the redeployment of tactical nuclear weapons back to South Korea, we are told that this is needed to reassure a jittery ally or to help prevent Seoul from seeking its own nuclear deterrent. Neither argument can withstand serious scrutiny. Land-based nuclear weapons in South Korea are not reassuring, nor are they needed. The United States is already signaling readiness to come to South Korea’s defense, including by nuclear weapons’ use, by many other means, including bomber over-flights. These signals have not altered Kim Jong Un’s behavior. Repositioning tactical nuclear weapons won’t, either.

As for the nonproliferation argument, as long as Washington and Seoul remain strong allies, South Korea will not build nuclear weapons. All bets are off, however, if the Trump Administration initiates a war on the Korean Peninsula featuring heavy casualties and mushroom clouds, whether small or large. The surest path to nuclear proliferation in South Korea and elsewhere is for Trump to ruin alliance ties.

 Michael Krepon is Co-Founder of the Stimson Center. This piece originally ran in Arms Control Wonk on October 4, 2017.

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