Many Americans were aghast at President Donald Trump’s announcement this month that he would meet with North Korean dictator Kim Jong Un.

But in moving toward diplomacy, Trump is following in the steps of previous presidents. If he continues down their path, the end result would be a deal that allows Pyongyang to keep its nuclear weapons — not because Trump gets taken in by Kim, but because such a deal boosts American interests. Since World War II, the United States has labored to prevent nuclear weapons from spreading. But once a country has them, Washington ultimately accommodates it, opting to develop some kind of diplomatic influence, if not control, over other nuclear powers, instead of going to war.

This pattern reflects the pragmatism embedded at the heart of American nuclear policy. While the United States makes principled efforts to ensure nonproliferation, policymakers understand that it is in American interests to make the best of nuclear proliferation when it occurs. Thus, in spite of saber-rattling, Washington may well consider how it can make a nuclear North Korea work for the United States.

Dating back to World War II, the United States has tried diligently to limit nuclear proliferation. After successful American nuclear tests, President Harry Truman brusquely shut off British access to information about the American bomb, despite the role that the British played in the Manhattan Project.

Yet once Britain had exploded its first device in 1952, American diplomats reversed course, launching lengthy atomic negotiations with their British counterparts. The result: The United States would provide Britain with wide-ranging nuclear assistance in exchange for far-reaching U.S. control over British nuclear decision-making. Ultimately, the United States and the United Kingdom partnered to become the “nuclear directorate” of NATO.

The American attitude toward a French-driven European nuclear weapons program was largely similar. To stop Europeans from acquiring nuclear weapons, Washington tried to persuade them to self-impose restrictive nuclear agreements via Euratom, the European Atomic Energy Community. But in 1957, when France rejected these efforts and embarked with European partners on a strategic weapons initiative, the United States did not forcefully oppose it so long as it was coordinated within the U.S.-dominated framework of NATO.

When France subsequently ended European strategic cooperation and developed its own nuclear weapons, Washington sought to incorporate the French nuclear strike force — the force de frappe — into NATO’s joint strategy. The United States repeatedly offered France nuclear assistance in return for adjusting its nuclear program to American policy preferences. But preferring nuclear independence, France chose to remain outside NATO’s nuclear decision-making mechanism, which was dominated by the United States. Yet by 1974, NATO, with U.S. backing, agreed that even an independent French nuclear force would contribute to its goals for deterrence, establishing a basis for cooperation among Britain, France and the United States that continues today.

The American posture of accommodating nuclear powers hasn’t simply applied to allies. At the time that China joined the nuclear club in the 1960s, it was one of the world’s worst dictatorships. Between 1958 and 1962, under Mao Zedong’s “Great Leap Forward” reforms, about 45 million Chinese died. In 1966, Mao unleashed upon the Chinese people the havoc of the Cultural Revolution — a quasi civil war to reassert his authority. Within this domestic context, China developed its nuclear weapons.

While U.S. policymakers considered military options to destroy the Chinese nuclear infrastructure, Washington ultimately opted to turn a nuclear China to America’s geopolitical advantage. When President Richard Nixon and Henry Kissinger “opened” China in 1972, their key motive was to balance the emerging Chinese — nuclear — power against the Soviet Union. Subsequently, Washington may even have supported the Chinese nuclear program, by sharing still-secret intelligence on Soviet missile tests and giving China access to computer technology usable for warhead design.

Similarly, while Washington initially enacted sanctions after Indian and Pakistani nuclear weapons tests in 1998, it subsequently sought to develop nuclear cooperation with both countries. A 2006 U.S.-Indian nuclear deal gave India access to American dual-use technology in exchange for an implicit U.S.-Indian nuclear alliance against China. And while Washington’s dialogue with Islamabad on nuclear issues has been fraught with difficulties, the United States has turned to cooperative programs, ranging from combating proliferation to reinforcing Pakistani command and control structures, to try to influence Pakistan’s nuclear policy.

During the Cold War, the United States even worked with its professed enemy, the Soviet Union, on bilateral nuclear arms control, nonproliferation diplomacy over Europe and the development of crisis communication. After the end of the Cold War, Russia agreed to maintain close technical nuclear cooperation with the United States. Washington moved to secure Russian fissionable materials, to prevent Russian nukes from becoming “loose” and to keep Russian nuclear weapons experts from selling their sensitive knowledge to the highest bidder.

This close partnership lasted until 2016, when Moscow declined to participate in the U.S.-initiated Nuclear Security Summit process and subsequently suspended cooperation with Washington on the conversion of fissionable materials.

Throughout 70 years of nuclear diplomacy, the United States has employed the same tactic: first trying to prevent nuclear proliferation, and when those efforts failed, opting for cooperation over conflict. Accommodating new nuclear powers has allowed Washington to bring them into the U.S.-dominated international system, aligning them with American geopolitical interests.

In view of limited American resources, the accommodation approach seems most pragmatic, both in the past and today. While the United States may not yet be ready to accept a nuclear North Korea, that calculation may change, given the high military and political costs involved in trying to end the North Korean nuclear weapons program forcefully. As a result, the United States may fall back on its tried and true method — accepting Kim Jong Un’s nuclear program in exchange for concessions that help Washington to pursue its broader geopolitical interests in Asia.

Elmar Hellendoorn is a post-doctoral fellow at the International Security Program and the Project on Managing the Atom at the Belfer Center for Science and International Affairs, Harvard Kennedy School.

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