Secretary of State John Kerry walks to his car with Austria’s Foreign Minister Sebastian Kurz, right, as he arrives at Vienna International Airport, in Vienna, Austria, Wednesday, Oct. 15, 2014. Kerry meets Wednesday in Vienna with Iranian Foreign Minister Mohammad Javad Zarif to try to advance nuclear talks and meet the target date of Nov. 24. (AP Photo/Carolyn Kaster, Pool)

Fifty years ago today, the People’s Republic of China conducted its first nuclear test.  This caused great alarm among American policymakers, who feared that an emboldened China would use its nuclear arsenal to promote revolution abroad and draw regional states into its political orbit. U.S. officials were also acutely concerned that the Chinese test would unleash a kind of nuclear “domino effect,” with countries like India, Japan, Australia, Indonesia, and Taiwan developing their own nuclear weapons in response. This could lead states like West Germany, Israel, Pakistan, and Egypt to conclude in turn that they must follow suit.

President Lyndon Johnson ordered the formation of the Task Force on Nuclear Proliferation to study this problem. It involved a distinguished group of former government officials and private citizens led by former Deputy Secretary of Defense Roswell Gilpatric.  As historian Frank Gavin has documented, the committee considered a wide range of options but ultimately recommended the adoption of a much stronger U.S. nonproliferation policy. The result was a major policy shift that included the scrapping of selective proliferation schemes like the Multilateral Force and culminated in the Nuclear Non-Proliferation Treaty (NPT) in 1968. Following India’s nuclear test in 1974, U.S. policies were strengthened further with the adoption of automatic sanctions policies embedded in the U.S. Foreign Assistance Act and the Nuclear Non-Proliferation Act.

Even though five decades have passed, experts disagree over whether these policies were successful. Some public commentators and academics describe U.S. nonproliferation policy as a failure, emphasizing the inability of the U.S. government to arrest the nuclear programs of Pakistan, North Korea, or Iran.  On the other hand, a large body of recent academic research on nuclear proliferation either pays little attention to U.S. policy or argues that there was not much proliferation for the United States to prevent. According to this school of thought, nuclear domino effects are a myth that have been proven historically invalid; leaders’ understanding of their state’s identity, domestic regime type, or the strategic characteristics of nuclear weapons make them much less attractive and “contagious” than traditionally believed. Research on the NPT, meanwhile, has seen it as a set of norms that affect states’ understanding of appropriate behavior, while downplaying the role of coercion and power.

In contrast, my own research suggests that nuclear domino effects are real and that U.S. policy has been crucial in preventing them from reaching fruition.  In the wake of the Chinese nuclear test, for example, India, Japan, Taiwan, and Australia all began moving toward developing a nuclear arsenal. U.S. efforts were important in preventing Japan, Taiwan, and Australia from following through. Moreover, while the U.S. failed to prevent India from testing in 1974, it responded by strengthening its nonproliferation policy further, instituting automatic sanctions policies that I argue have deterred states that are dependent on the United States from pursuing nuclear weapons. The policy has helped decrease the rate at which states begin to develop nuclear weapons programs. It also explains why recent proliferators have exclusively been “rogue” states outside the U.S. sphere of influence like Iran, North Korea, Iraq, and Libya. This stands in stark contrast to the roster of U.S. friends and allies that pursued nuclear weapons before the strengthening of U.S. policy, i.e. South Korea, Taiwan, Pakistan, Israel, and France.

This evidence is only one part of a burgeoning research program that is uncovering the long underappreciated role of American nonproliferation policy, including its efforts to prevent nuclear tests, induce compliance with the NPT, or coerce some of its closest allies into remaining non-nuclear. Much of this research has drawn on recently declassified documents from the National Security Archive and Cold War International History Project and has benefited from the support and resources of the Stanton Foundation and Nuclear Studies Research Initiative.

The lesson of this research is clear. Examples of the “failures” of U.S. nonproliferation policy like Pakistan and North Korea are conspicuous and therefore receive more press. In contrast, the successes are often invisible, because they involve states’ tacit decisions not to start nuclear weapons programs. American citizens and policymakers should not lose sight of the broader success of U.S. nonproliferation.

Nick Miller is the Frank Stanton Assistant Professor of Nuclear Security and Policy in the Department of Political Science and Watson Institute for International Studies at Brown University.