28 January 2016

The indelicate balance of nuclear modernization

Adam Mount

Adam Mount

Adam Mount is a senior fellow at the Center for American Progress. Previously, he was a Stanton Nuclear Security Fellow at the Council on Foreign Relations. Before that, he worked on nuclear...


In 1983’s The Wizards of Armageddon, journalist Fred Kaplan describes the grim work of the RAND Corporation at the end of the 1950s. Over the course of that decade, RAND analysts had warned that US Strategic Air Command forces were dangerously vulnerable. The analysts cautioned that bombers stationed overseas were at risk of being hit by a Soviet first strike before they could reach their targets, and that therefore it was necessary to disperse and defend them. These arguments were instrumental in shaping modern nuclear strategy and the US arsenal throughout the Cold War.

The goal behind these arguments was to establish what the eminent RAND systems theorist Albert Wohlstetter called “the delicate balance of terror.” This phrase served as the title of a classic 1958 article in which he argued that the American public and US defense planners had been dangerously sanguine about the nuclear balance. Wohlstetter reasoned that a country’s possession of nuclear weapons was not sufficient to establish deterrence if the adversary had a reasonable expectation of limiting damage from those weapons. As technology evolved and countries improved their nuclear arsenals, the delicate balance of terror tilted constantly, and therefore nuclear deterrence had to be assiduously maintained.

Today, many observers continue to think of the nuclear balance as delicate. There is a strong impulse in the United States to maintain capabilities that mirror those of its adversaries and materially respond to new developments. Concerns that New START may be in Russia’s favor, calls to react to Russia’s violation of the Intermediate-Range Nuclear Forces Treaty, and proposals to build new nuclear weapons all imply anxiety that the nuclear balance could tilt abruptly and give an adversary an advantage. Many share the concerns of Alabama Republican Rep. Mike Rogers, chairman of the House Armed Services Subcommittee on Strategic Forces, who said at a December hearing that he is “greatly worried that the United States stands the risk of losing the next arms race to Russia and China.”

A belief in the delicacy of the nuclear balance is also behind efforts to reduce and eliminate gaps in US capabilities. For example, some are calling to accelerate procurement of the new long-range stand-off missile to cover a hypothesized gap in the US Air Force’s ability to strike certain targets in highly defended areas with a lower-yield warhead than those found on ballistic missiles. (Brookings Senior Fellow Steven Pifer recently referred to the long-range stand-off missile as “an insurance policy for the insurance policy.”) The gap could arise just prior to 2030 if the new B-3 bomber is delayed and the B-2 bomber is incapable of reaching certain targets. How much should the country be willing to spend to diminish the risk of this gap? If the balance of terror is delicate, perhaps quite a lot.

But is the balance of terror still delicate? If it were, it would be essential for the United States to precisely calibrate its arsenal to its adversary’s capabilities every year. Modernization would be a perilous period, creating gaps in capabilities that would have to be filled. Strategic considerations would tend to override political, diplomatic, and fiscal concerns. The fact is, though, that the nuclear balance is not as delicate as it once was, and we are living in a time of acute fiscal austerity and manifold military priorities. Risk, moreover, is an inherent part of nuclear strategy. If Washington can’t learn to live with risk, the cost of closing small and hypothetical gaps in the nuclear arsenal will be paid in harsh currency: by sacrificing conventional military priorities, the welfare of citizens, and the country’s long-term ability to compete in a changing world.

A different worldA great deal has changed since Wohlstetter’s essay appeared in the 1950s, at a uniquely transformative time for the nuclear balance. The United States was only beginning to construct the triad of nuclear systems—bombers, land-based missiles, and submarines—that serve as the framework of the modern arsenal. Whether these procurement efforts would succeed was, Wohlstetter wrote, “wildly uncertain.” The first US intercontinental ballistic missile (ICBM), the Atlas, had been test-flown the year before. Just six years later, the Atlas was obsolete, replaced by the Titan II. At sea, the United States was regularly deploying a small handful of rudimentary Regulus cruise missiles; the Polaris missile would enter service in 1961, improving on its predecessor’s range by a factor of five. In the skies, the Air Force had just deployed the B-52, its first intercontinental bomber, and was exploring radical new aircraft concepts.

In short: in the late 1950s and early 1960s, the nuclear balance was rocked by major qualitative changes to delivery systems. Nuclear deterrence theory was still highly unsettled, with strategists struggling to understand the consequences of the missile revolution. Even as they were preparing for a protracted competition with the Soviet Union, US defense planners could not reliably estimate the price, capabilities, or reliability of their new systems.

This kind of uncertainty is difficult to imagine today. Today’s nuclear triad has changed little in the quarter century since the end of the Cold War. It is made up of a few highly reliable systems that each serve a defined purpose. Each leg of the triad is meant to serve as a hedge against the catastrophic failure of another, and for the most part there are hedging options within each leg. Though every system in the US arsenal will have to be modernized in the coming years, the new systems will mostly replicate existing capabilities.

This strongly suggests that the nuclear balance is far less delicate than when Wohlstetter wrote. There are few uncertainties about any country’s nuclear systems and how they interact with one another; each nuclear power has a valid expectation that it can deliver a nuclear strike against an adversary that attempts a first strike.

Living with riskThere is additional evidence that the nuclear balance is no longer delicate. Other countries tolerate significantly higher margins of risk in their nuclear operations. Among the nine nuclear weapon states, only the United States and Russia believe that they need more than a few hundred warheads to deter their adversaries. France operates a sea- and air-based nuclear dyad, while Great Britain relies on a monad that consists of a single type of warhead attached to Trident II missiles leased from the United States. China’s development of nuclear capabilities has been gradual and minimal; only now is it approaching an assured second-strike capability.

Even Russia seems comfortable accepting significant risk. Consider, for example, its early-warning capability, a complex system of satellites and radars aimed at providing advance warning of incoming nuclear strikes. Russia allowed the system to deteriorate. Though it is actively upgrading its early-warning ground-based radar network, for more than a year, it had no functioning early-warning satellites, let alone a complete constellation that would have afforded global coverage. The last remaining satellites of the old Oko system both failed to maintain their orbits in the fall of 2014. While Russia had intended to begin deploying its new system, EKS, in 2009, it finally did so only in November, 2015.

As nuclear physicist Pavel Podvig has written, though “the stated goal of the program was to ... provide comprehensive coverage, the objective at the level of practical decisions seems to have been …more limited.”The Russian early-warning system has sporadically had the ability to detect a massive missile attack, but has never been able to provide assurances against limited strikes or weapons with uncertain trajectories like submarine-launched ballistic missiles. Russia has accepted significant and protracted gaps in its early-warning coverage.

Contrast Moscow’s approach to Washington’s. The US early warning system, the Defense Support Program, has provided continual coverage for 30 years. It is now being replaced by two upgraded systems, the SBIRS (space-based infrared system) constellation in geosynchronous orbit, and the low-Earth orbit STSS (space tracking and surveillance system). The SBIRS will be supplemented by both the STSS and an ongoing effort to develop defensive systems against niche capabilities. For example, JLENS—the joint land-attack cruise missile elevated netted sensor system—aims to install blimps above Washington to guard against the possibility of nuclear cruise missile attacks launched from submarines offshore. (A JLENS blimp recently escaped its mooring.)

Russia’s greater propensity for risk acceptance is also reflected in other areas of its arsenal. For example, it operates only about 70 percent of the number of launchers the United States does, largely because it chooses to maintain several warheads on each of its ICBMs, a practice the United States ended in July 2014. The pattern also extends to submarines: Russia plans to build only eight next-generation Borei submarines, whereas the United States plans 12 replacements for the Ohio class. And Russia’s smaller fleet also reportedly undertakes less frequent and shorter patrols over a limited area. 

False mathematics. These contrasts show that the way the United States interprets the demands of deterrence is exceptionally stringent. This rather luxurious understanding is the result of a favorable strategic situation: Technological sophistication and economic predominance mean that the United States can produce and maintain a larger and more capable force than any other country on the planet.

There are two separate questions at stake here. The first is whether rote qualitative or quantitative parity between the United States and Russia is a requirement for deterrence. Few observers truly believe this, but sometimes the thought slips into rhetorical statements. At a December Congressional hearing on Russia’s violation of the INF treaty, Principal Deputy Undersecretary of Defense Brian McKeon seemed to point to nuclear modernization as a way of addressing Russian provocations, saying, “we are investing in the technologies that are most relevant to Russia’s provocations.”

In fact, the United States sets requirements for its nuclear force structure in a more objective fashion. In discussing the Obama administration’s preparations for the 2010 Nuclear Posture Review and subsequent employment guidance, both White House and Pentagon officials describe an iterative process in which proposals passed back and forth between the two sides. Accounting for extended deterrence requirements, expected arms control efforts, commitments to reduce the size and salience of the US arsenal, military advice, and other concerns, military officials then provided the political leadership with a targeting analysis for a proposed force level. Parity is a useful rule of thumb, but the most important requirement for nuclear forces is that they be able to threaten those targets necessary to deter an adversary. Former Secretary of Defense Bill Perry told Arms Control Today that he doesn’t think parity “has anything to do with deterrence…that is a political argument.”It is this perspective that allowed the Pentagon to assert that Russia “would not be able to achieve a militarily significant advantage by any plausible expansion of its strategic nuclear forces.”

The second and more interesting question is how much risk the United States is willing to tolerate. Nuclear weapons necessarily involve risk—that a system will malfunction, an accident will occur, or deterrence itself will fail. In 1958, Wohlstetter warned that the country was unintentionally incurring enormous amounts of risk. Today, however, the US nuclear arsenal operates with a far lower level of risk than other countries.

In Washington these days, one hears the refrain that the United States can afford its extensive nuclear modernization plans if it makes them a top priority. This is quite right: The United States could take on new debt and sacrifice other conventional procurement programs in order to devote more funding to nuclear modernization. If accelerated, the new long-range standoff missile could plug a narrow gap between retirement of the old air-launched cruise missile and procurement of the new penetrating stealth bomber. An expensive life-extension program for the B61 gravity bomb and the nuclear-capable variant of the F-35 could preserve the modest deterrent and assurance benefits of a mere 180 weapons stationed in Europe. The country could build 12 new ballistic missile submarines to preserve its ability to strike promptly from both the Atlantic and Pacific Oceans—rather than just eight, which would allow it to strike promptly with fewer warheads from both oceans.

It is prudent to monitor and maintain the nuclear balance, as Wohlstetter exhorted us to do. But it is also prudent to examine the requirements of deterrence in the context of existing strategic and budgetary realities. Other countries understand that the nuclear balance is not so delicate that gaps or compromises in their force structure will prove catastrophic—and they don’t even have the United States’overwhelming conventional capabilities. At a time when China’s capabilities are expanding dramatically and when nuclear planners are unlikely to receive all the funding they request, the United States can and must learn to live with a level of nuclear risk.  

If Wohlstetter interpreted deterrence as demanding careful and constant cultivation of a delicate nuclear balance, diplomat and political scientist George Kennan encouraged a different interpretation. Writing four years before Wohlstetter, Kennan decried a sort of “false mathematics” that understood nuclear deterrence as a precise and calculable endeavor. “The sooner we can free ourselves from the false mathematics involved in the assumption that security is a matter of the number of people you can kill with a single weapon, the better off, in my opinion, we will be.”