Mearsheimer does claim that states rationally pursue security. However, the assumption that states are rational actors—shared by most contemporary realists—is a huge stretch. The original—and still most influential—statement of neorealist theory, Kenneth Waltz’s Theory of International Politics, did not employ a rational actor assumption, but rather appealed to natural selection—states that did not behave as if they sought to maximize security would tend to die out (or, as Waltz put it, ‘fall by the wayside’). In contrast to Mearsheimer, Waltz at least motivated his assumption of security-seeking, rather than simply assuming it.
In subsequent publications, Waltz argued that states would be very cautious with nuclear weapons, and that the risk of nuclear war was very low—almost zero. Setting aside the question of whether almost zero is good enough in the long term, this claim is very questionable. From outside the realist paradigm, Scott Sagan has argued that internal politics are likely to predispose some states—particularly new nuclear states with military-dominated governments—to risky policies.
In a recent critique of both Waltz and Mearsheimer (https://journals.sagepub.com/doi/full/10.1177/00471178221136993), I myself argue that (a) on Waltz’s natural selection logic, we should actually expect great powers to act as if they were pursuing influence, not security—which should make them more risk-acceptant; and (b) Sagan’s worries about internal politics leading to risky nuclear policies should be plausible even within neorealist theory, properly conceived (for the latter argument, see my section ‘Multilevel selection theory’).
Bottom line: When you dig down into neorealist logic,the claim that states will be cautious and competent in dealing with nuclear weapons starts to look really shaky. Classical realists like Hans Morgenthau and John Herz had a better handle on the issue.
Mearsheimer does claim that states rationally pursue security. However, the assumption that states are rational actors—shared by most contemporary realists—is a huge stretch. The original—and still most influential—statement of neorealist theory, Kenneth Waltz’s Theory of International Politics, did not employ a rational actor assumption, but rather appealed to natural selection—states that did not behave as if they sought to maximize security would tend to die out (or, as Waltz put it, ‘fall by the wayside’). In contrast to Mearsheimer, Waltz at least motivated his assumption of security-seeking, rather than simply assuming it.
In subsequent publications, Waltz argued that states would be very cautious with nuclear weapons, and that the risk of nuclear war was very low—almost zero. Setting aside the question of whether almost zero is good enough in the long term, this claim is very questionable. From outside the realist paradigm, Scott Sagan has argued that internal politics are likely to predispose some states—particularly new nuclear states with military-dominated governments—to risky policies.
In a recent critique of both Waltz and Mearsheimer (https://journals.sagepub.com/doi/full/10.1177/00471178221136993), I myself argue that (a) on Waltz’s natural selection logic, we should actually expect great powers to act as if they were pursuing influence, not security—which should make them more risk-acceptant; and (b) Sagan’s worries about internal politics leading to risky nuclear policies should be plausible even within neorealist theory, properly conceived (for the latter argument, see my section ‘Multilevel selection theory’).
Bottom line: When you dig down into neorealist logic,the claim that states will be cautious and competent in dealing with nuclear weapons starts to look really shaky. Classical realists like Hans Morgenthau and John Herz had a better handle on the issue.