My colleagues W.P.S. Sidhu and Sitki Egeli stress the importance of establishing international norms for missile nonproliferation, for example by expanding and strengthening the Hague Code of Conduct against Ballistic Missile Proliferation. But norms must apply to all parties equally if they are to be effective. If norms and regimes are imposed in a one-sided way, as is the case with the Missile Technology Control Regime, they can't mitigate the sense of insecurity that drives proliferation. The same is true of instruments built on double standards, such as the Nuclear Non-Proliferation Treaty. Double standards only exacerbate insecurity, inviting further proliferation.

Indeed, proliferators' motivations to proliferate deserve more attention than they usually receive. Among the 31 countries that possess ballistic missiles, nine are nuclear-armed nations that continue to strengthen their missile capabilities as an element of their nuclear arsenals. The other 22 either possess ballistic missiles as a legacy of the Cold War—or are involved in extreme regional tensions that involve at least one nuclear-armed state.

East Asia, for example, is locked in a vicious cycle of missile proliferation. South Korea and the nuclear-armed North have competed in ballistic missile acquisition and development since the 1970s. Recently, in response to North Korea’s fourth nuclear test and a test of an intermediate-range missile, Seoul agreed to deploy a US missile defense system, known as Terminal High Altitude Area Defense. Japan began joint development with the United States of a ballistic missile defense system after North Korea’s 1998 test of a Taepodong missile. And Taiwan, reacting to a massive deployment of short- and medium-range ballistic missiles by nuclear-armed China, has developed intermediate-range ballistic missiles capable of hitting valuable targets such as Shanghai.

Nations locked in tense situations such as these, and facing adversaries equipped with ballistic missiles, naturally perceive themselves as threatened (especially if their adversaries' missiles are armed with nuclear warheads). So they seek ballistic missiles of their own, both to gain a near-certain retaliatory ability in the event of a missile attack and to deter ground-based interventions. More to the point, they acquire ballistic missiles to defend themselves against weapons of terror—which is what missiles armed with nuclear warheads really are.

Making matters worse, nuclear-armed states are now developing "smart" nuclear weapons—more accurate, with lower yields, and thus more "usable." This is an extremely dangerous trend. If "smart" nuclear weapons in combination with short- and medium-range ballistic missiles were deployed amid a tense regional conflict, one could easily envision a contemporary Cuban Missile Crisis developing. Urgent action—and a new approach—are required to address the very real risk of theater nuclear warfare.

Mechanisms such as the Missile Technology Control Regime and the Wassenaar Arrangement have constrained and delayed ballistic missile proliferation, but they have failed to stop determined proliferators—especially non-regime members such as China, North Korea, Israel, India, and Pakistan. Any approach to missile proliferation that is merely technical and institutional may be doomed to fail. A new political approach is required—one that addresses proliferators' motives for proliferating.

Nearly 30 years after the Soviet Union and the United States concluded the Intermediate-Range Nuclear Forces (INF) Treaty, it's easy to forget how dramatic the treaty's impact was. Negotiations toward the treaty succeeded because they replaced the previous decades' spirit of confrontation with a spirit of mutual trust. Trust enabled comprehensive verification, on-site inspections, and actual reductions in nuclear weapons—and also fundamentally disrupted the Cold War. Within a few years the Berlin Wall had come down and the Soviet Union had collapsed. Arguably, the treaty played a key role in it all.

What's urgently needed now is a universal INF-style treaty that would eliminate the twin threats of missiles and non-strategic nuclear weapons. To be sure, negotiations toward such a treaty would be challenging. They would lack several advantages enjoyed during INF negotiations—the close balance between US and Soviet nuclear forces, for example, and the presence of a powerful antinuclear movement in Europe at the time. Today's world is far different, not least because it contains so many asymmetrical missile confrontations. But what really made the INF Treaty possible was bold political vision and a willingness to eliminate entire classes of weapons all at once. With a similar boldness of vision, non-strategic nuclear weapons and the missiles to carry them could disappear from Earth—just as surely as US and Soviet intermediate-range nuclear weapons once did.