Shen Dingli is Professor and Executive Dean of the Institute of International Studies, Fudan University.
The answer to the question 'Is the age of extended deterrence over?' cannot be a clear one. It is neither a firm 'yes' nor categorical 'nay'.
To start with, nuclear deterrence has both succeeded and failed. On the successful part, the US kept the secret of Soviet participation in the Korean War from the public to contain the likelihood of crisis escalation that may have led to direct conflict with a nuclear Soviet Union. Also during the Korea War, China was deterred by the US nuclear arsenal, which partly explained China's acceptance of the armistice.
On the unsuccessful part, America, despite its possession of nuclear weapons, did not deter North Korea's attack in 1950 or that of the Viet Cong in the 1960s-70s. China has even proclaimed a no-first-use policy, refusing to deter the US from selling weapons to Taiwan, though Beijing deems Taiwan a core national interest.
America's extended nuclear deterrence has also had a mixed record. The credibility of US extended deterrence for its NATO allies has not been challenged, and it assured nuclear nonproliferation among them. Nevertheless, America's virtual ally, Israel, has gone nuclear despite the US security commitment. During the 1970s, South Korea and Taiwan clandestinely launched their nuclear weapons programs for fear of US withdrawal from East Asia.
Recent trends seem to indicate the acceleration of the irrelevance of extended nuclear deterrence. If Pyongyang might not have been completely responsible for sinking the Cheonan, at least it didn't mind US extended deterrence for South Korea when it launched its artillery barrage against Yeonpyeong. The US didn't dispatch USS George Washington to the West Sea/Yellow Sea in the wake of Cheonan sinking. Even if the US did so after the artillery exchange in November 2010, it still didn't retaliate militarily against North Korea.
America mistakenly entered Iraq in 2003 under the pretext of Saddam's WMD build-up. However, Iran's persistent nuclear quest, regardless of various IAEA and UNSC warnings, has ridiculed any international pressures, including US deterrence. Israel is increasingly under pressure to launch a pre-emptive strike against Tehran so as not to burden US extended nuclear deterrence.
Beyond the seeming decline of extended nuclear deterrence, the aforementioned trend is also indicative of America's caution in wielding the nuclear option. What is at stake is not deterrence or extended deterrence, but security assurance per se. The US has actually not loosened its security commitment to its allies, but in order to maintain the credibility of its deterrent, America is now less willing to coerce its non-nuclear rivals while it has increasingly more non-nuclear tools in its policy kit. This was manifested in the Obama Administration's Nuclear Posture Review last year.
Both North Korea and Iran have understood this, to their benefit. Iran understands that its violation of various UNSC resolutions would at most incur a non-nuclear US response. Indeed, UN Secretary General Ban Ki-moon is mediating a nuclear swap arrangement to lessen international concern, which could legitimise Iran's uranium enrichment. North Korea has also ventured into crises short of inviting US military strikes, and it has presented its own conventional deterrence plus a looming nuclear deterrent. Deterrence is no longer a US gadget.
Mutual nuclear deterrence among major powers is indeed less relevant nowadays, in a globalising age. At a co-dependent time, there are more incentives for inter-state compromise and reconciliation, while contingencies which require a nuclear showdown are implausible — hence the decline of nuclear deterrence among major powers, and extended nuclear deterrence backed by various non-nuclear options.
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 US Army Korea - IMCOM.
