Bruno Tertrais is a Senior Research Fellow, Fondation pour la recherche stratégique, Paris, France.
Shen Dingli and Hugh White make valuable points in their contributions to the debate on extended deterrence opened by The Interpreter. However, they also construct strawmen, which limits the value of their arguments.
Shen Dingli mentions the 1950 invasion of South Korea; but at that time, there was no US extended deterrent to South Korea. The bilateral treaty was signed in 1953, after the war, in order to prevent a resumption of hostilities. His other example is the Vietcong war against Saigon; but likewise, at that time South Vietnam was not covered by an explicit defense commitment which promised retaliation against the North in case of aggression. And the Vietnam war was very different from the Korean one: it was more a slow-motion escalation than a full-scale state attack.
Finally, the case of Iran's 'persistent nuclear quest' is irrelevant to extended deterrence. It is true that 'Iran's violations would at most incur a non-nuclear US response', but so what? That has nothing to do with extended deterrence. For sure, one can argue that Washington and the other four permanent members of the UN Security Council have so far failed to deter Iran from continuing its nuclear march, and that Tehran's nuclearisation would have far-reaching consequences for US extended deterrence in the region. But that is a completely different debate.
Shen Dingli's contention that extended deterrence did not prevent the bombing of Yeonpyeong is much more relevant and interesting.
It could indeed be argued that Pyongyang was testing the limits of US protection to Seoul. However, another intriguing possibility should be raised: that North Korea was very careful to strike a 'disputed' area, one which was – at least from its point of view – not part of the territory covered by the US umbrella. In so doing, it may have acted like Egypt and Syria did in 1973: facing a nuclear-armed adversary, they were very careful not to attack Israel on its 1948 borders.
Hugh White raises an extremely important question: he wonders if Washington would threaten nuclear war for the sake of the Baltic states, since the risk of 'losing Europe' would be limited. In other words, the stakes would be much lower than during the Cold War. But, as in most discussions about deterrence, one has to consider the problem the other way round: would Moscow take the risk of invading the Baltic states, given that it would face three nuclear-armed adversaries and risk a military escalation that could, ultimately, end up in a nuclear exchange?
My answer is 'no'. It may be precisely because Georgia was not under NATO or US protection that Russia considered it could take a chance in 2008. (Incidentally, here again we see an intervention on what was arguably a disputed area: the Abkhazian and South Ossetian territories. Western reaction could very well be what stopped Moscow from going further.)
White also quotes with appreciation the reported 1996 statement by a Chinese official, according to which the US cares more about Los Angeles than it does about Taiwan. However, during a crisis in the Taiwan straits, the 'deterrence dialogue' would not stop there. The question is: what would Washington tell Beijing if China threatened to escalate the conflict to the US homeland? My guess: the US president would say 'try me'.
In other words, the credibility of the US extended deterrence to Taiwan depends not on the relative values of Taiwan and Los Angeles for Washington, but on the respective beliefs of Chinese and American officials about the sequence of a US-China nuclear war. A classic deterrence issue.
Shen Dingli makes a different but related point when he states that globalisation and interdependence have made nuclear deterrence among major powers less relevant than it used to be. That may be true, and there is something like a 'financial balance of terror' between Washington and Beijing. But I would caution against definitive conclusions: the First World War erupted at a time of (then) unprecedented economic interdependence between the major European powers of the time. This did not trump political passions and the strength of ideologies.
UPDATE: I described in an earlier post the 1950 North Korean attack as a 'failure of extended deterrence'. I should clarify what I meant. There was no formal extended deterrence to South Korea at that time. But by stating that the Korean peninsula was not part of the defensive perimeter of the US, Washington signaled explicitly to North Korea and its allies the absence of such a deterrent and gave a green light to the invasion.
The Nuclear Reactions column is supported by the Nuclear Security Project of the Nuclear Threat Initiative, as part of a wider partnership between the NSP and the Lowy Institute.
Photo by Flickr user The US Army.
