Time is not right for US no-first-use

Even if you favor a US nuclear no-first-use policy, you'll likely admit that such a policy could have negative security repercussions in Asia. So it is in this roundtable: My roundtable colleague Ta Minh Tuan, who hopes that Barack Obama will institute no-first-use, recognizes that such a shift could embolden Kim Jong-un to press ahead even harder with North Korea's nuclear arms program and to undertake additional provocative actions.

But what if no-first-use encouraged Kim, free from the fear of nuclear retaliation, to mount a conventional attack against South Korea? This is just the sort of scenario that causes some US security experts to hope that the Obama administration does not adopt a "sole purpose" policy for Washington's nuclear arsenal. The administration, with its 2010 Nuclear Posture Review, already moved closer to renouncing the use of nuclear weapons except in response to a nuclear attack by an adversary. Moving further in that direction would not be wise at this point.

Any indication that the United States might be retreating from its nuclear guarantees would compel Japan and South Korea to take countermeasures—which would likely extend beyond the deepening dependence on US protection that Ta discussed in Round One. Rather, Tokyo and Seoul might well go nuclear themselves. This would represent a worst-case scenario—two additional cases of the very nuclear proliferation that Washington works so hard to prevent.

Ta does admit that Japan and South Korea, "with an ambitious and nuclear-armed North Korea next door," would have valid reasons for concern about a US no-first-use policy. But then he asserts that Tokyo and Seoul would have "no legitimate reason… to develop their own nuclear weapons—as long as US extended deterrence remained in place." This is a bit cavalier. Ta may be a true believer in the notion that, overall, US no-first-use would benefit regional peace and security. But he underestimates the alarm with which Japan and South Korea might view no-first-use.

Ta also largely ignores a major Asian security problem that no-first-use could aggravate: China's claim of sovereignty over nearly all the South China Sea. Beijing's land reclamation projects, and its militarization of reefs and shoals in the Spratly and Paracel Islands, have strengthened China's military capacity in contested waters—and have also alarmed the United States, Japan, and most Southeast Asian nations, including the Philippines, Vietnam, and Singapore. The Permanent Court of Arbitration in The Hague issued a ruling in July that legally repudiated China's claim of sovereignty and its land reclamation projects, but Beijing has rejected the verdict. It is persisting in its plan to project power across the South China Sea by reclaiming (and building an air strip on) Scarborough Shoal, which is only 140 miles from Manila.

US Secretary of Defense Ashton Carter has explicitly warned Beijing of countermeasures if China goes ahead with such measures. In recent months the United States has taken muscular measures such as sending aircraft carrier battle groups—in defense of the principle of freedom of navigation—on close passes by China's artificial islands. China's ambitions and its increasingly aggressive behavior in the South and East China Seas have become a focus of rising tensions between China and the United States (as well as Washington's regional allies). In such a geostrategic context, no prudent US leader can afford the luxury of initiating a nuclear no-first-use policy.