First Strike Nuclear Capability: Is It a Sound Defense Policy?

The spread of nuclear weapons to potential US adversaries raises important questions for US nuclear strategy and foreign policy. During the Cold War, US nuclear strategy was designed to meet the challenges posed by the Soviet Union, a superpower adversary with an enormous nuclear arsenal. Today, the United States faces a strikingly different environment. A few regional adversaries have acquired or are attempting to acquire a small number of nuclear weapons and the ability to deliver them at long range. Few would disagree that the United States should attempt to deter nuclear attacks by threatening to inflict unacceptably high costs with nuclear retaliation. But should it also plan to use nuclear weapons to destroy an adversary’s nuclear weapons in either a preemptive or retaliatory strike? Although current US nuclear strategy says yes, the question has not been thoroughly studied. In Counterforce Revisited: Assessing the Nuclear Posture Review’s New Missions(1), Charles L. Glaser and Steve Fetter analyze this controversial question, finding at most a very limited set of scenarios in which these nuclear counterforce missions increase US security. Are Nuclear Weapons Required to Destroy Opposing Nuclear Capabilities? For a variety of ethical, political, and military reasons, the United States would prefer to use conventional weapons to destroy an adversary’s nuclear force. However, US doctrine identifies targets that might have to be attacked with nuclear weapons, including hard and deeply buried targets and mobile targets. Glaser and Fetter show, however, that conventional weapons can destroy or disable many of these targets. In addition, they find that nuclear weapons would not be highly effective against some of the targets that conventional weapons cannot destroy. There is, however, one class of targets—moderately deep and precisely located underground facilities—that can be destroyed only with nuclear weapons. The United States should consider using nuclear weapons to destroy these targets only if they are strategically vital—that is, their destruction is essential to protect the United States from nuclear attacks. Glaser and Fetter suggest that few, if any, targets meet these criteria.

The Potential Benefits of Counterforce Missions

If conventional weapons are incapable of destroying the adversary’s ability to attack with nuclear weapons, there may be valuable counternuclear roles for US nuclear weapons. The potential benefits can be divided into three types: deterrence, damage reduction from enemy nuclear attacks, and enhanced US ability to pursue its foreign policy objectives.

Deterrence—A key argument for counterforce capabilities is that they could improve the ability of the US to deter nuclear attacks by denying an adversary a survivable nuclear capability, that is weapons the United States cannot destroy that could be used later in a war. According to this argument, an adversary that could hold some nuclear forces in reserve is more likely to launch a limited nuclear attack against the United States because its remaining nuclear forces might deter US retaliation. Although the logic of this argument is sound, Glaser and Fetter argue that adding nuclear counterforce is unlikely to significantly enhance the US deterrent. The United States already possesses a range of potent deterrent capabilities, including the threat to inflict massive societal damage with nuclear weapons and the ability to invade and conquer with conventional weapons. Although an adversary’s survivable nuclear capabilities might raise some doubts about the credibility of US threats, deterrence is likely to be effective because relatively little credibility is sufficient when the costs of retaliation are so large.

Damage limitation—The argument for damage limitation is more straightforward and compelling than the argument for deterrence. The United States can try to understand what might deter an adversary from attacking with nuclear weapons, but it cannot guarantee that deterrence will succeed. Therefore, the ability to destroy the adversary’s capacity to use nuclear weapons—and thereby reduce the damage of an attack—could be invaluable. Glaser and Fetter accept this argument, but caution against exaggerating the benefits of damage limitation: if deterrence is successful, damage limitation is unnecessary and the United States can adapt its foreign policy to avoid conflicts in which deterrence is most likely to fail.

Foreign policy advantages—A common concern is that acquisition of nuclear weapons by a potentially hostile state could hurt US foreign policy, enabling an adversary to deter the United States from intervening in a regional conflict or from initiating a conventional war. Some have suggested, for example, that a key reason that the United States invaded Iraq but not North Korea, which posed a much larger nuclear threat, was that the latter had a small number of nuclear weapons. Even if US prospects for deterring escalation are good, it will have compelling reasons for staying out of conflicts that have even a small probability of escalating to nuclear attacks unless US interests are very large. Proponents, therefore, argue that nuclear counterforce options—either preemptive or retaliatory—are necessary to restore the ability of the US to pursue its foreign policy objectives. Glaser and Fetter argue, however, that this benefit to US foreign policy could well be outweighed by the increased probability of nuclear war. A United States that bargains harder in a crisis because it believes it can protect itself from nuclear attack could also be more likely to be attacked by a determined adversary.

The Risks of Counterforce Missions

Increased probability of nuclear attacks—An adversary with nuclear forces that are vulnerable would have greater incentives to use some of them early in a conventional war to gain the bargaining advantages of nuclear escalation before its force is attacked. In addition, the vulnerability of the adversary’s nuclear force could increase the probability of accidental and unauthorized attacks. A country attempting to ensure its ability to launch its weapons often has to take measures that reduce its ability to prevent “rogue” commanders from launching their weapons without orders from the national leadership. A doctrine that emphasizes nuclear counterforce options could also increase the probability that the United States would unnecessarily escalate a conventional conflict—striking preemptively when, in fact, its adversary was not going to attack. If some of the adversary’s force survives, it might then launch a retaliatory nuclear attack against US interests.

Damaging the nuclear taboo and nonproliferation regime—Critics worry that adopting nuclear counterforce missions will encourage states to acquire nuclear weapons, undermine the US ability to prevent this proliferation, and make adversaries more willing to use nuclear weapons. Glaser and Fetter argue that these effects are likely to be small. US counternuclear capabilities do not increase states’ basic incentives for acquiring nuclear weapons, which reflect their conventional military and nuclear inferiority. The nuclear taboo against the use of nuclear weapons has not been sensitive to US nuclear doctrine; therefore, including counterforce options is unlikely to make nuclear use more acceptable. At the same time, US policies that emphasize the value of nuclear weapons are inconsistent with the spirit of the nonproliferation regime and, therefore, risk weakening it.

Policy Implications

A limited, but relatively unappealing, role for nuclear counterforce missions may exist. Counterforce may reduce the risks associated with an adversary’s nuclear weapons capabilities, but not to the extent that the United States will be able to pursue its foreign policy goals as it might have before proliferation. Even when US interests in a regional conflict are high, the possibility of devastating nuclear attacks against US cities or regional allies should constrain its foreign policy and military actions. For example, the option of initiating a conventional war with a nuclear adversary for the purpose of changing its regime through invasion should be taken off the table. More generally, the United States will need to accept that its nuclear strategy cannot solve the problems and dangers created by the proliferation of nuclear weapons to regional adversaries.

Even if the United States adopts a more circumscribed foreign policy vis-à-vis emerging nuclear states, there may be cases in which truly vital interests are at stake. If once involved in this type of conflict the United States believes its adversary is preparing a nuclear attack and if there are critical targets that can be destroyed only with nuclear weapons, then using nuclear weapons to limit damage might be the best option. Glaser and Fetter believe such cases are likely to be extremely rare, but cannot rule out the possibility. To make sound decisions, US policymakers must fully appreciate the limits and uncertainties of US damage-limitation capabilities, the risks of escalation and retaliation, and the extent of collateral damage that would result from attacking specific targets.

To moderate the potentially negative proliferation impacts of including nuclear counterforce missions in its doctrine, the United States should bring other components of its nuclear policy into line with its nonproliferation regime obligations, including cutting the size of its nuclear arsenal and making it clear that it will not test new nuclear weapons.