I am deeply grateful to Francis J. Gavin for his thoughtful and generous review of Defending Frenemies. I am particularly honored to have my book reviewed by one of the foremost thinkers in the “renaissance of nuclear security studies” (Scott D. Sagan, “Two Renaissances in Nuclear Security Studies,” 2014).

Like any good reviewer, Gavin raises a number of questions about my book, and I would like to briefly respond. My disagreement with him does not center around the “success” of the United States’ strategy of nuclear inhibition during the Cold War; that is, whether the number of nuclear-armed states, including US allies and friendly states, is lower today than it otherwise would have been absent Washington’s nonproliferation efforts. In fact, I repeatedly state that my neoclassical realist theory does not purport to explain the nuclear proliferation success (or failure) of the targeted ally, but only the inhibition strategies that US policy makers pursued toward that ally.

Were the containment of rival great powers and the inhibition of nuclear proliferation consistently pursued as coequal pillars of US grand strategy over the past seven decades? Gavin argues that they were. By contrast, I argue that in dealing with certain allies in the Middle East, South Asia, and East Asia, US policy makers generally prioritized containment over nonproliferation. Nina Silove contends that when political scientists and historians write about “grand strategy” they often inadvertently conflate three distinct concepts—grand principles, grand plans, and grand patterns of behavior (“Beyond the Buzzword: The Three Meanings of ‘Grand Strategy,’” Security Studies, 27 [1], 2017). Perhaps Silove’s taxonomy can be illustrative here. Gavin and I agree that nuclear inhibition was and is a grand principle for the United States; it certainly became so by the Kennedy administration. We disagree, however, over whether the pursuit of nuclear nonproliferation among allies and friendly states outside of Europe was actually a grand pattern of behavior for the United States.

Gavin raises some good questions about my case selection and my categorization of certain allies as “frenemies” of the United States. He asks, What makes a state a frenemy, as opposed to an ally, neutral, or adversary? I define a frenemy as a state located in a volatile region that has an ongoing bilateral security relationship with the United States, despite the existence of divergence in the security interests and political objectives of the two parties. To be a frenemy, the weaker ally should display a pattern of deception, manipulation, evasion, or even obstruction of the expressed interests of its superpower patron. Each of the states I selected—Israel from the early 1960s to the early 1970s, Pakistan from the mid-1970s to the late 1980s, and South Korea and Taiwan in the 1970s—engaged in these behaviors, not only with respect to their clandestine nuclear weapons program but also in their overall security relationships with Washington.

I note that “frenemy” is just one of several ideal types of asymmetric alliances (the other ones being special relationships, ambivalent alliances, and alliances of convenience) that exist along a continuum. Over time these relationships can evolve or regress along a continuum. For example, although today the United States and Israel have a special relationship, that was certainly not the case in the early 1960s. The Kennedy administration tried to inhibit the clandestine Israeli nuclear program by insisting on periodic “visits” by US scientists to the Dimona reactor complex, while at the same time rebuffing David Ben Gurion’s requests for a mutual security treaty and only grudgingly agreeing to transfer antiaircraft missile systems.

As Gavin notes, my sample excludes a number of states formally allied with or at least friendly to the United States, including Australia, Japan, Italy, and Sweden, that either had nascent nuclear weapons programs or tried to keep their nuclear options open in the 1960s and early 1970s. Instead, I selected cases outside the main theater of superpower competition, in which the geopolitical interests of the United States and the protégé did not always overlap and where the protégé had good reason to doubt any American security guarantees. (Indeed, it was fear that the United States would withdraw forward deployed troops and seek a rapprochement with China that prompted South Korea and Taiwan to initiate clandestine nuclear weapons programs in the first place.) However, given the small universe of cases of states that had dedicated programs to develop nuclear weapons since 1945 (26 by my count), it is difficult (if not impossible) to identify a representative sample of US allies or friendly states that sought to acquire nuclear weapons.