Zachary Keck is deputy editor of e-International Relations and an editorial assistant at The Diplomat. His commentary has appeared at Foreign Affairs, Foreign Policy, World Politics Review and Small Wars Journal.

Even as other issues surrounding Iran’s nuclear program are debated, there is a wide-ranging consensus in the West that an Iranian bomb would precipitate a regional nuclear-arms race, if not a global one. Senators Lindsay Graham (R-SC), Robert Casey (D-PA) and Joseph Lieberman (I-CT) said as much in the pages of the Wall Street Journal in March. Similarly, British foreign secretary William Hague worries that if Iran acquires a nuclear weapon, “the most serious round of nuclear proliferation” to date would commence. And recently in the New York Times, Ari Shavit of Haaretz stated matter-of-factly that “an Iranian bomb will bring about universal nuclear proliferation.”

Fortunately for mankind’s sake, there is no evidence to support these apocalyptic prophecies. Although some precautionary actions might be prudent, neither history nor contemporary circumstances indicate that an Iranian atomic weapon would be a nuclear catalyst.

Historical Precedents

To begin with, fears of an impending nuclear tipping point have been a regular feature of the nuclear age. The CIA is a case in point. Whereas in 1957 the agency predicted ten countries could go nuclear within a decade, by 1975 it concluded that “logically” nuclear proliferation would only subside when “all political actors, state and non-state, are equipped with nuclear armaments.” A quarter century and one nuclear power later (both South Africa and Pakistan acquired a nuclear-weapons capability during this time, but South Africa dismantled all its nuclear weapons by 1991), CIA director George Tenet announced in 2003 that we had entered “a new world of proliferation” and warned “the ‘domino theory’ of the twenty-first century may well be nuclear.”

The 1960s were equally remarkable...