The Challenge of Nuclear-Armed Regional Adversaries

Motivations and perceptions such as those discussed in Chapter Three point to some insights about possible future behavior. For example, if the desire for greater influence and prestige were a factor motivating the regime's pursuit of nuclear weapons, then it follows that, once the weapons are operational, the regime is likely to act in ways that reflect the belief that it is entitled to greater influence and respect, at least at first. History supports this: New nuclear powers seem to undergo a process of learning and adjustment as they attempt to gauge the utility of their new weapons. As part of this process, a new nuclear power may take actions intended to test the responses and limits of other powers. In the past, these tests most often occurred in the diplomatic sphere, although there are some cases of limited acts of aggression, often through proxies.One early historical example of this type of behavior was General Secretary Josef Stalin's approval in 1950 of Kim Il Sung's plan to invade South Korea. Prior to January 1950, Stalin had repeatedly turned down Kim's request for military support, fearing that a war in Korea would spark a wider confrontation with the United States, for which the Soviet Union was unprepared. However, after the Soviet Union tested its first atomic weapon in September 1949, Stalin seems to have been convinced that a "second front" was feasible in East Asia and that the United States, in the face of the Soviet Union's atomic potential, was unlikely to respond.³ Another example from the Cold War period was China's attack on Soviet border forces in 1969. This mostly forgotten incident, which is one of few direct confrontations between two nuclear powers, provides further indication that new nuclear powers may believe that they can engage in limited military confrontation with more powerful adversaries despite the risks of retaliation.

Notwithstanding these considerations, it is important not to overestimate the utility of nuclear weapons. To date, nation-states have not found them to be useful as instruments of overt military aggression. While the possession of nuclear weapons may allow North Korea and Iran to pursue more vigorously objectives that run counter to U.S. interests, it seems likely that these adversaries will do this in a constrained fashion. In fact, we have no historical cases in which an emerging nuclear power undertook large-scale military aggression to advance revisionist claims. So we do not foresee a nuclear-armed North Korea becoming likelier to invade South Korea. Nor do we expect that Iran would use nuclear weapons, should it acquire them, as a shield to facilitate large-scale conventional aggression against Saudi Arabia, the Persian Gulf states, or adversaries further afield, including Israel.

Pending the fielding of much more effective capabilities for preventing an enemy from using nuclear weapons, it seems clear that the United States will be compelled to temper its objectives vis-àvis regional adversaries when those adversaries possess even modest numbers of nuclear weapons that can be delivered only to targets in their regions. The distinguishing feature of the post–Cold War security environment has been the United States' ability to impose its will on recalcitrant states that resort to violence in persistent violation of international norms. The fact that the United States possessed military forces whose capabilities were unquestionably superior to those of its potential adversaries made this possible. This "golden era" of conventional power projection may be coming to a close in important parts of Eurasia. If the United States and its allies cannot find ways to neutralize small arsenals of nuclear weapons or prevent them from being delivered to targets outside of their home countries, they will have to accept that military operations to impose regime change must be reserved for situations of only the direst sort.

Such a scenario will perhaps appear manageable, if not attractive, to Western strategists. We would lament the potential loss of the option to "finish the job" with impunity against an adversary, but the "nuclear weapons as last-ditch deterrent" scenario grants the initiative to the side whose conventional forces are dominant: As long as U.S. leaders understand where the enemy's red lines lie, they can prosecute military operations up to those points and then assess the balance of risks and gains before considering their strategy for war termination. However, it would be imprudent to assume that future nuclear-armed adversaries will necessarily behave in this way. There are several reasons for this.First, adversary leaders may fear that their lives and their regimes are at grave risk from the very outset of the conflict. In Afghanistan and in Iraq, the United States demonstrated that it had the intention, if not the capability, to kill enemy leaders by bombing the buildings they were thought to be occupying. And while those particular attacks failed to kill their intended targets, the regimes themselves were overturned within a matter of weeks following the commencement of serious fighting. To the extent that U.S. forces are credited with the capability to carry out decapitating strikes or to rapidly take down enemy regimes, the belief will likely grow that one must act early to stop the U.S. military operation before it is too late.