The Obama Administration has had to overcome several obstacles to reach a framework agreement with Tehran on Iran’s nuclear program. One source is the unsubtle attempt of Israel and its neoconservative allies in the United States to sabotage any prospective agreement. Another major impediment, though, is Tehran’s suspicions that Washington would not live up to its commitments if Iran dialed back the scope of its nuclear ambitions. Iranian officials, with good reason, wonder whether the United States has abandoned its policy of forcible regime change when it comes to dealing with adversaries.

Indeed, Washington’s conduct over the past three decades has badly undermined its overall global nuclear nonproliferation policy. Numerous factors determine whether a technologically capable country decides to forego or pursue the development and deployment of nuclear weapons. Worries about the capabilities and intentions of regional security rivals, opportunities for greater prestige and influence, concerns about the probable reaction of neighbors and the overall international community, and cost considerations all play a role. And, in some cases, the existence of a threat from outside the region can be a decisive factor. 

The emergence of Israel, India, and Pakistan as nuclear powers reflected the complex interplay of those various considerations. Pakistan worried about India’s far greater population and growing edge in conventional military capabilities. The periodic wars between the two countries underscored to Pakistani officials the desirability of deploying a small nuclear arsenal as a military equalizer, despite the financial costs and diplomatic fallout. For India, not only was an unpredictable Pakistan a source of worry, there were security concerns regarding a power outside South Asia: an increasingly capable and assertive China.

Israel faced a similar set of incentives to go nuclear. Badly outnumbered by its Muslim neighbors, Israeli leaders feared that someday the country’s conventional military advantage might erode. Deploying a nuclear arsenal (albeit an unacknowledged one) was an ace in the hole. That move also sought to intimidate Israel’s larger, but nonnuclear neighbors, ensuring the country’s continuing regional preeminence.

For U.S. adversaries, Washington’s conduct creates a significant incentive to develop a nuclear deterrent. Regimes that are on bad terms with the United States have witnessed how U.S. administrations treat nonnuclear opponents. The U.S.-led NATO assault on Serbia, first over the Bosnia civil war and then to sever the restless province of Kosovo, was a graphic object lesson regarding the extent of Washington’s military power and the willingness of U.S. leaders to use it. That episode was especially alarming since Serbia posed no credible threat to the security of the United States.

George W. Bush’s decision to invade and occupy Iraq could only have reinforced the worries of nonnuclear adversaries. Again, Washington brought America’s vast conventional military superiority to bear against a weak country—and did so on the basis of bogus allegations of a threat to U.S. interests. Iranian leaders, in particular, had a ringside seat for that war, and they certainly noted that outspoken American hawks intimated that Iran—as a member of the so-called Axis of Evil—might be next on Washington’s hit list.

Finally, any remaining inclination that Iran and other nonnuclear opponents of the United States might have to avoid incurring the economic and diplomatic costs of barging into the global nuclear weapons club dissipated further when Libyan dictator Muammar Gaddafi abandoned his program in exchange for promised concessions from the United States and its allies. Within a few brief years, those nations turned on Gaddafi, openly funding and arming an insurgency to overthrow his regime. That campaign culminated with NATO (primarily U.S.) cruise missile strikes to support the rebel offensive. 

The Libya episode hardly created an incentive for Iran, North Korea, and other potential nuclear-weapons states to forgo such ambitions. Indeed, it reinforced the opposite incentive. The pertinent lesson seemed to be that only a very foolish government would give up the nuclear option in exchange for the promise of normalized relations with the West.

Washington’s armed belligerence toward nonnuclear adversaries is not the only pertinent factor inducing Iran and North Korea to consider building nuclear weapons. (Iran certainly is focused on both Israel and the Saudi-led Sunni regional bloc.) But U.S. conduct is far from an irrelevant factor. The alarming hawkishness of recent U.S. administrations has, however inadvertently, badly undermined Washington’s professed desire to prevent the proliferation of nuclear weapons. America has become its own worst enemy regarding that objective.