This Is Why Countries Still Build Nuclear Weapons in the 21st Century

Editor’s note: An earlier version of this article was published on The Diplomat on July 03, 2013.

Throughout the nuclear era, the conventional wisdom has been that when one state acquires nuclear weapons, its adversaries follow suit. As former Secretary of State George Shultz so eloquently put it: “proliferation begets proliferation.”

Although some of the earliest nuclear proliferation cases followed this pattern, it has been increasingly rare in recent decades. That’s likely because in the dawn of the atomic era, non-nuclear countries had little reason to believe nuclear adversaries would exercise unilateral restraint in using these awesome weapons. However, as the taboo against the first use of nuclear weapons has become more entrenched, non-nuclear states have become increasingly confident that they do not need their own arsenals to avoid becoming the victim of a nuclear attack.

Just because nuclear weapons are not needed to deter nuclear attacks does not mean these weapons have not proven to be strategically useful. In fact, nuclear weapons have proven incredibly effective at deterring large-scale conventional attacks. Not surprisingly, then, the primary security factor driving nuclear weapons proliferation today is conventional military weakness. This is likely to continue in the future, with profound consequences for which states do and don’t seek nuclear weapons.

Although the conventional military balance has become an increasingly important factor in states’ decisions to seek or forgo nuclear weapons in recent decades, it wasn’t completely negligible in earlier years. France’s pursuit of a nuclear weapon is a case in point. The conventional narrative says that France decided to build nuclear weapons because of  Charles De Gaulle’s intense nationalism and lack of faith in America’s nuclear umbrella.

The archival record does not completely support this interpretation, however. To begin with, as Jacques Hymans finds from his careful review of the available documents, it was Mendes France, not De Gaulle, who made the first crucial decisions to pursue the bomb. The timing of President France’s decision is illuminating: he initiated the nuclear weapon program three days after NATO agreed to West Germany’s rearmament despite Paris’ objections.

President France’s rationale was straight forward. As Hymans explains, he believed that “French military power must remain at least one order of magnitude superior to Germany’s; thus, the fewer the restrictions on German conventional weapons, the greater the need for a French atomic force.” Given that France had lost three wars to Germany since 1870, including WWII where Berlin occupied France for years, his decision isn’t too hard to comprehend.

Israel’s decision to pursue the bomb was also motivated almost entirely by its perceived conventional inferiority vis-à-vis its Arab neighbors. Although these neighbors did not possess nuclear weapons, Israeli leaders in the 1950s and 1960s–most notably David Ben Gurion and Shimon Peres– were convinced the survival of the Jewish state depended on it possessing a large qualitative edge against its much larger Arab neighbors. This is not surprising given that Egypt alone is 55 times larger than Israel and, in 1967, had about eleven times its population.  Israeli leaders therefore calculated that acquiring a nuclear weapon was the surest way to offset this inherent conventional imbalance, and thereby ensure the Jewish state’s survival.

As the nuclear taboo has become more entrenched over the decades, states have had less to fear from a neighbor acquiring an atomic weapon. Consequentially, conventional military power has surpassed enemy nuclear weapons in terms of its importance in driving nuclear proliferation.

North Korea illustrates this dynamic nicely. Although Pyongyang began its nuclear program during the Cold War, it only started making substantial progress in the late 1980s and early 1990s. Notably, this was when the nuclear threat it faced was declining as South Korea abandoned its nuclear ambitions in the 1970s and the U.S. withdrew its nuclear weapons from South Korea in 1991 (and had been drawing them down substantial in the decades before then).

By contrast, the 1980s and 1990s was also the time when the conventional military balance shifted decidedly away from North Korea’s favor. To begin with, in the late 1980s the Soviet Union began pursuing relations with South Korea, and North Korea ultimately lost its great power protectorate when the USSR collapsed in 1991 (before then its aid to North Korea began declining as Moscow’s economic woes mounted). The new Russian state quickly established diplomatic ties with South Korea, as did China in 1992. Furthermore, whereas North Korea boasted a larger economy than its southern neighbor through the mid-1970s, South Korea’s rapid economic ascendancy, combined with its inherent demographic advantage, ensured that its latent military capability increasingly outpaced Pyongyang’s. And that is without even accounting for Seoul’s military alliance with the United States.

Of course, the U.S. military is part of the equation on the Korean Peninsula, and its stunning victory in the first Gulf War left little doubt about its conventional dominance in the post-Cold War era. Undoubtedly, North Korean leaders watched the U.S. armed forces crush Saddam’s army with growing trepidation. This was ominous indeed for policymakers in Pyongyang, who rightly calculated that they couldn’t match America’s conventional military might. Consequently, they sought to negate its military superiority by acquiring the ultimate deterrent.

The Islamic Republic of Iran’s nuclear program has followed a similar trajectory. Although the initial decision to restart the Shah’s nuclear program was motivated almost entirely by Saddam Hussein’s nuclear and chemical weapons programs, Tehran only began making real progress on the nuclear front in the middle to late 1990s. Saddam Hussein can hardly explain this trajectory, given that his threat to Iran was significantly diminished following the first Gulf War, and it was eliminated entirely after 2003.

Iran’s nuclear program is better explained, then, by the growing threat Tehran saw from the United States. This began when America established a large military presence in the Persian Gulf following the First Gulf War. It only grew a few years later when, in July 1995, Washington decided to reactivate the 5th Fleet after a 45-year hiatus. Suddenly, America’s imposing naval forces were a constant presence in Iran’s coastal shore.

Further underscoring this danger to Iran, the following year President Bill Clinton signed the Iran and Libya Sanctions Act of 1996, confirming that President Akbar Hashemi Rafsanjani’s outreach to the U.S. had failed. The U.S. threat to Iran has only grown more precarious since 2003; not surprisingly, Iran’s nuclear program has made its greatest advances during this time.

The conventional military balance’s primacy in influencing horizontal nuclear proliferation is also evident from the states that have not chosen to go nuclear. For instance, no Northeast Asian country went nuclear following China or North Korea’s nuclear tests, nor did Israel’s nuclear arsenal cause a nuclear arms race in the Middle East.

Recognizing the centrality of conventional military power in driving nuclear decision-making helps us better anticipate future proliferation threats. For instance, if Iran acquires nuclear weapons, its neighbors will be unlikely to follow suit. Not only do these states lack the necessary technical capacity, but Iran lacks the ability to project conventional military power (Iran’s greatest threat to these countries comes from its support for proxy groups, which nuclear weapons are not effective at deterring.)

On the other hand, China’s growing conventional military power makes it likely that Eastern Asia will be the region where the most potent proliferation risks emanate from. Countries with territorial disputes with China—first and foremost, Japan— will have the strongest motivation to build the bomb. Unfortunately, for non-proliferation advocates, many of China’s neighbors—especially Japan but also South Korea— already have robust civilian nuclear programs. This breakout capability will only make it more tempting for policymakers to order a mad dash for the bomb.

Another potential area of concern is in Eastern Europe where Russia has already dismembered two states in the last decade as part of its bid to re-establish a sphere of influence. Moscow’s neighbors cannot possibly hope to compete with Russia’s conventional military power, and thus may look to the ultimate weapon to ensure their survival.