Nuclear weapons won't necessarily make Iran more aggressive

That Iran—surrounded by rivals with nuclear ambitions and singled out by the United States, the largest military power in the world—has an interest in nuclear weapons is not surprising. Even assessments that view Iranian behavior as a challenge to U.S. interests in the Middle East do not consider the regime as threatening as the PRC was during the 1960s. As Shahram Chubin writes, “It is not overtly confrontational or given to wild swings in behavior or to delusional goals; it has not denounced arms control treaties to which it formally adheres; and there is evidence of pluralism and some debate within the country.”³⁶ Nuclear weapons could make Iran more aggressive. Or, as with China, they could provide international legitimacy and security, making Iran less aggressive than it has been. As one recent analysis put it, “If anything, Iran might and that possession of a nuclear weapon actually diminishes its op- tions in the Middle East and forces it to act with greater restraint.”³⁷ A deeper understanding of nuclear history and the underlying geopolitical circum- stances Iran faces makes the prospect that it would take actions (such as supplying Hamas or Hezbollah with nuclear weapons) that could invite its own destruction highly unlikely.³⁸

One might argue these findings are not applicable to Iran, due to that country’s unique culture and religion and its distinct geopolitical and economic motives to develop nuclear weapons. However, the fact is that almost all states that have developed nuclear weapons have stumbled into a crisis out of inexperience and then authorized more moderate nuclear strategies and foreign policies after a few years’ experience. This “experience effect” in the cases of the United States (in Korea), the Soviet Union (in Hungary), the United Kingdom (in Egypt) and France (in Algeria), cases in the late 1940s and early 1950s, are likely attributable to the early Cold War as well as nuclear weapons. It is not clear that fear played a role here, because the uncertainty associated with the early Cold War drove the conflict propensity of the new nuclear powers. However, all inexperienced nuclear powers since the late 1950s have found themselves in conflicts and wars either trying to revise a status quo (Soviet Union and Pakistan) or preventing and/or coercing a revisionist nuclear power from doing so (India). In China’s case, nuclear weapons seem to have emboldened the Chinese to respond more forcefully to aggressive Soviet patrolling of disputed territory. In some cases whether the new nuclear power is revising or defending the status quo is unclear, because many other factors are also changing in a particular region, for example Israel and South Africa. Nevertheless, the fact that countries as different as the Soviet Union in the early 1960s, China in the late 1960s, and Pakistan in the early 2000s exhibited strikingly similar variation in their fundamental choices of coercive or moderate nuclear strategies shows that the great nuclear learning phenomenon knows no cultural or geographic bounds even though these countries exhibit important dif- ferences. The effect of experience with nuclear weapons on the central elements of their nuclear strategies over time is striking.

Nevertheless, one can overstate both the probability and the effectiveness of blackmail. It is again useful to recall that analysts expressed similar fears about China when it acquired nuclear weapons, yet Beijing's behavior for the most part did not validate those fears. Although China did attack Vietnam in 1979, the PRC's conduct since the late 1960s has generally been less, rather than more, bellicose than it was when China lacked a nuclear capability. That episode illustrates the larger point that nuclear weapons are much more useful as a deterrent against possible adversaries than they are as a mechanism for intimidating those adversaries, much less for war-fighting purposes. There are indications over the past several years that the two newest nuclear powers, India and Pakistan, have reached that conclusion. As in the case of China after the 1960s, New Delhi and Islamabad appear to have become more cautious and restrained since they built nuclear arsenals. One cannot guarantee that Tehran would follow that pattern, but by the same token it is unwarranted to assume that the Iranian regime would engage in rampant blackmail.

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.