Recently, I posted a review of Leon Panetta's Worthy Fights. In it, I took issue not only with some of Panetta’s comments on the use of nuclear weapons in the case of a conventional attack but on some of the broader ambiguities in US nuclear policy. In particular, I questioned whether—or in what sense—a “nuclear umbrella” even existed, and got push back from from Bruce Klingner at the Heritage Foundation and and Terence Roehrig of the Naval War College; yesterday I provided an overview of that debate; today, I take up the issue of whether such statements augment the credibility of our deterrent, or whether they may even be counterproductive.
Given our conventional as well as nuclear superiority, it is hard to imagine a circumstance under which North Korea would launch a conventional, let alone, nuclear attack. But if they did, it is not clear that the US would use nuclear weapons or would need to. First, it is clear that they would not use them for counter-value strikes; it would be completely against our political objectives—not to mention moral considerations—to bomb North Korean cities. Yet even the use of tactical nuclear weapons—for example, in a circumstance where the North Koreans had managed to achieve tactical surprise and the capacity to reinforce forces on the peninsula was set back—seems unlikely. Would any sitting president cross the nuclear threshold? And if not, is invocation of nuclear weapons really credible?
Roehrig tends to agree that the likelihood of nuclear first use is highly problematic for reasons related to military utility, norms (ala Nina Tannenwald’s Nuclear Taboo and T.V. Paul’s Tradition of Non-Use), collateral damage, fallout drifting over neighbors, and the fact that they United States has far more credible conventional options that have similar strategic effects. Nonetheless, he notes that despite an inherent credibility problem in the nuclear umbrella, even a small chance of nuclear retaliation may have an important deterrent effect. To quote Denis Healey, British Secretary of State for Defence who formulated the “Healey Theorem” concerning Europe: “it takes only five per cent credibility of American retaliation to deter the Russians, but ninety-five per cent credibility to reassure the Europeans.”
Roehrig thinks that dynamic may be at work at least to some extent in Asia as well. Moreover, the very concept of the “nuclear umbrella” remains an important element of the U.S. commitment because it has become interwoven into the security architecture and become an important political as well as military signal of the overall strength of the alliance.
Klingner goes farther, arguing that a strategy of no first use—which would limit use of nuclear weapons only to managing nuclear threats or attacks—is counterproductive and even destabilizing. Since we know that we will not initiate hostilities, a commitment to no first-use would allow our opponents—most notably the North Koreans—to initiate conflict at the time and circumstances of their choosing, i.e. when it is to their greatest advantage and our disadvantage. The US and its allies could then find themselves in a situation where even our high tech conventional weapons are insufficient. Rather than accepting defeat (including the subjugation of our allies), the US might need to use nuclear weapons against military targets (e.g. leadership facilities or massed forces) even if North Korea only used conventional forces. This need would increase if conventional attack was coupled with bio/chem attacks or nuclear threats against South Korea, the United States and Japan.
Both Roehrig and Klingner argue that these issues need to be placed in the context of Japan in particular. North Korean nuclear threats could, for example, deter Tokyo from allowing the US to use bases in Japan. There have been conflicting statements during the past month between Prime Minister Abe and US officials whether the US can use the seven UN-designated bases on Japan for Korean contingencies without specific permission to do so. My colleague Marc Noland reports on a conversation (under Chatham House rules) with a Japanese analyst saying that Japan might well not grant permission to that end, precisely because of concerns about getting dragged into the conflict.
However, it seems odd to be having an intense debate about the credibility of the US nuclear deterrent without asking why we think North Korean threats of this sort carry any credibility. This is particularly true given the fact that the US is capable of controlling the escalation ladder on the Korean peninsula through conventional means. US nuclear posture in central Europe during the Cold War was a function of Soviet/Warsaw Pact conventional superiority; the situation on the Korean peninsula is completely different.
Moreover, the desire to maintain a nuclear option in the case of conventional attack carries three not insignificant disabilities.
- The first concerns crisis stability. The more likely path to conflict on the peninsula is not through a large-scale conventional attack, but through escalation of a lower-level conflict, for example along the Northern Limit Line. Were such a crisis to escalate, North Korea could find itself believing its own rhetoric: that the country was vulnerable to a US first strike. In such a circumstances, there would be perverse incentives to “use them or lose them.”
- Second, the continual invocation of the nuclear umbrella compounds a problem that Klingner himself has written on extensively; the tendency of both alliance partners to underspend on their own conventional defense. For the record, Klingner does not believe that alliance underspending is a result of the nuclear umbrella. But there is a logic, even if only at the margin. If you are a South Korean and believe that your country is powerfully protected by a credible nuclear deterrent, why spend money on conventional forces?
- Finally, the continued emphasis on the role that nuclear weapons might play vis-à-vis North Korea (and Iran) has the perverse effect of generating hard-line opposition to giving up its nuclear capacity. How do you deter a nuclear strike with a degraded conventional force without having a nuclear force of your own? North Korean rhetoric—while quite possibly disingenuous—continually emphasizes the role of the “nuclear umbrella” in justifying its own nuclear force. Although these arguments are somewhat less compelling with respect to North Korea—with its long history of seeking nuclear weapons, the could matter looking forward and certainly have an influence in the more pluralist political environment of Iran.
US policy is clearly is evolving. As Klingner notes, given the increasing capability of conventional weapons (PGMS, bunker-busters, etc.), the US could accomplish missions through conventional means that in the past might have required nuclear weapons. And as Roehrig points out, the statements such as those made in the Consultative Security Meetings include at US insistence reference not only to nuclear weapons but to conventional strikes and defensive capabilities as well. But following this very useful exchange, it is still not clear to me that the nuclear umbrella actually exists, at least as sometimes conceived, that it is necessary, is credible or adds to the stability of the Korean peninsula or the wider region.