During Secretary of State John Kerry's recent trip to East Asia, Chinese and U.S. officials reiterated their strong commitment to a non-nuclear Korean Peninsula. North Korea is clearly the principal threat to that goal, since Pyongyang has already conducted three nuclear tests, including one in February of this year. Some experts speculate that the DPRK already has enough fissile material to build several bombs, and leaks from a U.S. Defense Intelligence Agency report in mid-April indicated that the North may now have the ability to shrink the size of a nuclear device sufficiently to create a missile warhead. Although the report added that such a nuclear-armed missile would have "low reliability," it sparked a flurry of concern in the United States and throughout East Asia.
A less obvious, but increasing, possibility is that South Korea might dash hopes of keeping the Peninsula non-nuclear. Two opinion polls taken in South Korea, including one by Gallup Korea, after the North's February nuclear test found that more than 64 percent of respondents favored Seoul developing its own nuclear deterrent. It was not an entirely unprecedented result. Following the North Korean attack on Yeonpyeong Island in 2010, polls also showed a surge in public support for an independent deterrent.
It's pertinent to recall that South Korea had an active nuclear program during the 1970s under strongman Park Chung-hee. Only massive pressure from Washington induced Seoul to terminate that program. But nervousness in South Korea has been building steadily since the United States and the other participants in the Six-Party talks have been unable to get Pyongyang to relinquish its nuclear objectives.
A pro-nuclear attitude seems to be slowly spreading within South Korea's political class as well as among the general public. Although President Park Geun-hye (ironically, the daughter of the man who originally flirted with building an independent deterrent) has rejected any nuclear ambitions for her country, there has been a noticeable increase in statements from major political figures and opinion shapers in recent months taking a very different position.
The most outspoken politician thus far on the nuclear issue is Chung Mong-joon, and Chung is not some inconsequential, fringe player. Not only is he a member of the South Korean parliament, but he's the son of the founder of the powerful Hyundai industrial conglomerate and one-time leader of the governing party.
During a visit to Washington in early April, Chung stated that South Korea should withdraw from the Nuclear Nonproliferation Treaty and, if the North continued its nuclear program, match that move with the development of its own nuclear weapons. A few weeks earlier, he was quoted in the New York Times explaining his reasons. "The Americans don't feel the North Korean nuclear weapons as a direct threat," he said. "At a time of crisis, we are not 100 percent sure whether the Americans will cover us with its (sic) nuclear umbrella."
Chung's comment highlights a long-standing problem faced by allies or security clients of a great power like the United States. Primary or direct deterrence — deterring an attack on one's own county — is a straightforward process with high credibility. North Korea or any other aggressor knows that attacking the United States would be suicidal, since Washington would respond with a devastating retaliatory strike. But an ally or client cannot have similar confidence that its patron would take the same action to respond to an assault confined to that client. Such uncertainty is especially great when the aggressor has the ability to attack the homeland of the protecting power.
That's why the credibility of extended deterrence — the willingness to incur possible devastation merely to defend an ally — has always been lower than the credibility of primary deterrence. During the Cold War, Washington's NATO allies were perpetually uneasy about whether the United States would actually defend them in a showdown with the Soviet Union. And as Henry Kissinger once noted, the allies constantly pressed the United States to reiterate and strengthen its assurances (including by stationing forward-deployed military units as a tripwire to ensure U.S. involvement if war erupted in Europe).
South Korea and other U.S. allies in East Asia experience a similar sense of uncertainty as evidence mounts that Pyongyang intends to retain and strengthen its nuclear capability. Although North Korea cannot presently strike the U.S. homeland, it may soon be able to attack Guam and other U.S. possessions in the western Pacific. And probably within a decade it will be able to reach targets in North America.
South Koreans have ample reason to wonder whether U.S. leaders would really risk the safety of their own country just to respond to a North Korean attack confined to South Korea. The Obama administration is trying to reassure its ally that the security commitment, including the nuclear deterrent, remains firm. The flyover by B-2 nuclear-capable bombers during the March joint military exercises with South Korea was a manifestation of that attempt to reassure — as was the subsequent dispatch of F-22s.
The credibility of Washington's security guarantee to Seoul is fading, though, no matter how often U.S. officials may profess the continued seriousness of that commitment. As much as Washington and Beijing insist that their goal is a nuclear-free Korean Peninsula, unless they can induce North Korea to give up its nuclear program, there is a growing possibility that South Korea will not sit idly by and depend solely on the United States to deter threats from a nuclear-armed, hostile neighbor. South Korean political leaders can resist a pro-nuclear majority in public opinion for only so long.
The issue of nuclear proliferation on the Korean Peninsula is a key test for the Sino-U.S. relationship and its ability to manage security problems. Beijing's patience with Pyongyang certainly appears to be wearing thin. Chinese President Xi Jinping's comment that "no one should be allowed to throw the region, even the whole world, into chaos for selfish gains" was widely seen as a rebuke to North Korea. But if Beijing wants the Korean Peninsula to be free of nuclear weapons, the time is overdue to put stronger pressure on Kim Jong-un's government — despite the risk that such pressure might cause the North Korean state to collapse, removing the strategic buffer between China and U.S- led East Asia.
If China needs to get tougher with Pyongyang, the United States needs to become less wedded to a strategy based on ever tightening sanctions and the goal of increasing North Korea's economic and diplomatic isolation. Instead, the Obama administration ought to take Beijing's long-standing advice and explore ways to try to establish a more normal bilateral relationship with Pyongyang — as difficult as that task might be.
The bottom line is that unless both China and the United States change their strategies, the goal of a nuclear-free Korean Peninsula will slip away. Moreover, Washington and Beijing may ultimately have to deal with not one but two nuclear-armed Korean states.