Of the three interwoven threats to America--terrorists, rogue states and the proliferation of WMD--the third has provoked the least public debate since 9/11. This is curious, since the invasion of Iraq was intended as an exercise in counter-proliferation and the administration has announced a major program to deal with other cases of the spread of WMD. But public debate has focused on the prudence of pre-emptive war and unilateralism, and on whether Iraq had stockpiled WMD in the first place, not on the ways the momentum can be and is being used to overcome further WMD threats in Libya and Pakistan and to strengthen the anti-proliferation regime more generally. The Bush Administration's ongoing program has received little serious attention outside of expert circles, despite eye-catching measures such as the Proliferation Security Initiative, which empowers the United States to board ships suspected of carrying WMD contraband.

Meanwhile Iran and North Korea demonstrate that the old non-proliferation regime is still in crisis. Yet at the same time, wider diplomatic conditions are better than at any point since the 1940s for a realistic policy of not only non- but even counter-proliferation--that is, the use of force to stop proliferation. Measures can be taken in the near future to reverse the impending crisis, and a short capsule history will explain why.

The history of non-proliferation diplomacy falls into three periods. The first was the period of U.S. nuclear monopoly that lasted from 1945 to 1949, during which robust plans for an anti-proliferation regime were proposed. In the late 1940s, the Baruch Plan proposed global management of uranium and UN enforcement actions that would have been exempt from a veto in the Security Council.

It was no accident that the Baruch Plan was drawn up at a time when there was a single power center on nuclear affairs--the United States--even though it avoided drawing on American power per se. A single cohesive global power center, pushing through standards and taking the steps necessary to enforce them, was needed if proliferation was to be prevented. Baruch was a proliferation pre-emption plan. Yet the Baruch Plan was stymied by the Soviets, who exercised their Security Council veto to avoid adopting the plan, thereby preserving the principle of Security Council veto in all matters, including the question of nuclear proliferation, which the Baruch Plan would have abolished. Thus it was doomed from the start.

Two different Western thinkers saw the logical next step. Bertrand Russell and James Burnham both advocated the preservation of America's nuclear monopoly by a preventive war threat against the USSR if it sought to build the bomb. Both saw U.S. power as the only available enforcement arm for non-proliferation. As the phrase went at the time, it was a matter of "using the atomic monopoly in order to preserve the atomic monopoly."

Realistic though this sounded, it was hugely risky. Preventive war was threatened not against a small rogue state but against one of the two surviving great powers--risking a world war with an uncertain outcome. Most non-communist countries were in ruins, revolutionary communism was a global force, and Soviet authority was buttressed by its decisive role in winning World War II. Though Russell and Burnham hoped to win by threat of war, the threat, to be convincing, would require a clear capacity to win.

Aware of these difficulties, Russell and Burnham iterated a political prerequisite for their policy: a union of the remaining free countries of Europe with America. This would provide a wider power base for victory and for subsequent stabilization. It would also serve legitimizing purposes, fitting the pre-emptive policy into the progress of world order: a united Europe-America already constituting, in Einstein's phrase, a partial world government. In short, it mixed the ideas of global empire and world government in a relatively realistic manner, setting up the main elements in embryonic form and dealing with imminent technological dangers.

But the Russell-Burnham policy ended along with American nuclear monopoly. The Soviet Union acquired the bomb in 1949. When Stalin died in 1953, the result was an immediate switch in Soviet diplomacy that brought the Korean War to an end and set the Cold War on more stable lines. Russell and Burnham then went their separate ways. Russell put his priority on nuclear disarmament and constructing neutral bridges back to a unified world; Burnham, on defeating communism to secure a Western-led world order. Russell became the grandfather of the New Left, Burnham, of the neoconservatives. Nuclear bipolarity had become an established fact; preventing further proliferation now became the main task of diplomacy.

The second period of non-proliferation, lasting from 1949 to 1989, was marked by the fact that there was no single power center capable of enforcing the rules. In the early 1960s, John Strachey, an anti-communist British Labour politician and strategist, called on America and the Soviet Union to constitute such a power center together and to enforce tough inspections--through preventive war if necessary. As with the Baruch Plan, however, Cold War rivalry prevented the Strachey Plan from getting off the ground.

To be sure, Mao accused the two superpowers of conducting a Strachey-like global "condominium" or "co-imperium." This was what he thought any two rational superpowers would do. (In the 1940s, the Soviets had similarly accused America of following the Russell-Burnham policy. They too thought any rational power would do this.) The reality was that America and the Soviet Union were in deadly competition for global power, even as they wished to cooperate on proliferation. So the standards were set--and set low--by negotiations among enemies. The result was an "international regime" whose workings were structured to slow proliferation rather than to halt or reverse it.

In the 1950s, the IAEA was founded to promote peaceful uses of atomic energy and to provide economic incentives for its non-military use. It soon became unclear whether this was restraining proliferation or promoting it. In the 1960s, the two superpowers took something from the Strachey proposal: They acknowledged a joint responsibility for non-proliferation and the management of the arms race, negotiated the Partial Nuclear Test Ban Treaty in 1963, and played a leading role in creating the Nuclear Non-Proliferation Treaty (NPT). This upgraded the IAEA's authority to conduct inspections in each signatory country, with a goal of providing enough transparency and confidence as to avert races for the bomb among mutually suspicious groups of countries. It also strengthened Russia's embryonic westward orientation, in contradistinction to China.

During the same period, having created an alliance system within the West designed, among other things, to limit proliferation, the United States proposed a specific roll-back in the 1960s: a Multilateral Nuclear Force for NATO. This would have integrated French and British nuclear forces with America's and provided a potential core for an ultimate reversion to unity of nuclear forces worldwide. Charles de Gaulle vetoed the idea, however, preferring an independent nuclear deterrent for France. Some Gaullist strategists argued that global proliferation would lead to stability--a view shared by Maoist China and Castroite Cuba and later taken up by the likes of Kenneth Waltz and, of course, by subsequent generations of rogue states.

Thus, while proliferation was not reversed, neither was it allowed to spread unchecked. The NPT-IAEA regime provided regular mechanisms to slow down proliferation while making further proliferation among its signatories illegal--except for the loophole that the treaty could be renounced (as North Korea has recently done). It divided signatories into those acceding as nuclear states and those acceding as non-nuclear states. It perpetuated the discrimination in their status already established. And it enlisted the self-interest of the established nuclear powers in protecting the importance of their nuclear status by limiting the size of their club.

Great Power Responsibilities

It must be emphasized here that the NPT regime reflected and built upon the traditional conception of the special responsibilities of great powers, which goes back at least to the Treaty of Westphalia. The great powers mutually attributed special rights and duties to one another. The small powers accepted the reality, as well as the unwritten prerogative of the great powers to amend occasionally the rules in order to preserve the system's fundamental principles. Indeed, international law was largely the creature of great power practice.

The responsibilities of the great powers naturally grew more urgent with the advent of nuclear weapons. Five powers were formally attributed special rights in the Security Council and given almost unlimited authority to do as they chose--when unanimous--in the name of preserving international peace and security. Other states, accepting the brutal lessons of the two world wars, legally endorsed this extraordinary abrogation of their sovereignty and ratified the UN Charter. Yet when the Cold War broke out, and as long as the Security Council remained divided, the great-power prerogatives were recognized informally as belonging unilaterally to the superpowers. It was the only possible basis for successful non-proliferation.

Yet this was a realpolitik that dared not speak its name. Both superpowers were formally committed to anti-imperialist ideologies derived from their respective revolutions. They took this seriously enough to cooperate symbiotically in ending Europe's overseas empires. They competed for the loyalty of these ex-colonies and knew no greater accusation to hurl at each other than "imperialist." It would have been hard for them to jointly discuss such an imperialist subject as forceful counter-proliferation.