The Evolving Nuclear Order: Implications for Proliferation, Arms Racing, and Stability

The 25 years since the end of the Cold War have seen several notable shifts in the global distribution of nuclear capabilities:

• • The Soviet Union (now Russia) and the United States have slashed their arsenals by roughly 75% from 20,000–30,000 warheads to 7,000–8,000.¹

• • France and Britain have also made substantial cuts, reducing their nuclear forces from 500 weapons at their peak to roughly 300 and 200, respectively.

• • Of the Cold War “big five” (the United States, Britain, France, Soviet Union, and China), only China has not reduced its stockpile, which is estimated at 250 warheads. Beijing has also made significant investments in modernizing its forces, developing new mobile intercontinental ballistic missiles as well as submarine-launched ballistic missiles.

• • Three new countries (India, Pakistan, and North Korea) have joined the list of acknowledged nuclear weapons states, and one (South Africa) has been removed.

• • Finally, in recent years a series of aspirants (Iraq, Libya, and Syria) have seen their nuclear ambitions foiled, while one (Iran) continues to press on toward the finish line.

What are the implications of these developments for the conduct of international relations, and, in particular, how are they likely to shape events in eastern Eurasia, a zone of strategic interaction that extends from the Korean Peninsula, down through the South Asian subcontinent, and into the Persian Gulf region? The essays in this roundtable have helped shed light on three aspects of this question: proliferation, arms racing, and stability.

Proliferation

Regarding the further spread of nuclear weapons, the next chapters of the story in the broader Middle East will depend a great deal on what happens in Iran. If Tehran succeeds in developing nuclear weapons, other states may feel compelled to follow suit, including Saudi Arabia and Turkey. If it does not, Israel may remain the region’s only nuclear weapons state.

In East Asia, those states most likely to contemplate pursuing nuclear status are also anxious friends and allies of the United States. Japan, South Korea, and (albeit implicitly) Taiwan have until now been content to take shelter under the U.S. nuclear umbrella. But they could come to doubt the reliability of U.S. guarantees in the face of North Korea’s new capabilities, China’s nuclear modernization programs, or, especially in the case of Japan, both developments taken together.

While this once-taboo topic has been discussed more openly in both Japan and South Korea in recent years, neither country shows any overt signs of moving to acquire its own nuclear forces. Still, as Noboru Yamaguchi explains in his essay, there is nothing in Japan’s “peace constitution” that absolutely precludes the possibility, should the nation’s leaders deem it necessary for self-defense. Like South Korea and Taiwan, Japan has shown an interest in acquiring rocket and cruise missile technology that could someday serve as the basis for an independent deterrent force. For the moment, however, the potential for further proliferation in East Asia remains latent.

Arms Racing

One of the main features of the Cold War competition between the United States and the Soviet Union was the interaction between their respective armaments efforts, including their offensive and defensive nuclear weapons programs. Although there are a number of competitive dyads emerging in Asia, and while the possibility exists for even more complex arrangements, the degree of interaction among the actors to date remains limited. As Benjamin Schreer describes, China’s modernization of its long-range nuclear forces appears to be motivated in large part by a desire to reduce its vulnerability to a possible U.S. conventional precision strike. An increase in the number of weapons deployed, perhaps on multiple warhead delivery systems, could also reflect concern over the possible thickening of the U.S. national missile defenses. For the moment, however, there is no strong evidence to support the view that China aims eventually to achieve nuclear parity with the United States. Nor are there any indications to suggest that Washington will respond to Beijing’s limited buildup with measures designed to retain (or reacquire) a...