Should South Korea pursue its own nuclear strategy?
Following North Korea's February 12 nuclear weapons test, the UN Security Council adopted tough penalties on Pyongyang. Along with a new round of financial sanctions, the council beefed up inspections of suspect cargo to and from the country and took steps to halt illegal activities by Pyongyang diplomats - all intended to squeeze North's nuclear and missile programmes.
But the sanctions do not address the more serious questions raised by North Korea threatening pre-emptive nuclear strikes on the US as well as threats against South Korea and Japan. To keep tensions from boiling over, should Washington let Pyongyang pout and rant with little additional pushback, banking that time will force the poor, isolated country to return to the bargaining table? Or, given the regime's penchant for risk-taking, ought the US itself double down and return its nuclear weapons to South Korean soil, leaving no doubt that it remains committed to Seoul's defence? Alternatively, should South Korea, concerned that Washington's economic challenges and fatigue with global leadership may fray its commitment to the South's defence, move toward nuclear weapons? Would either tack dangerously incite Pyongyang or make it more prudent?
These questions are not easy to answer, but attempting to do so gives a starting point to plot the future. On balance, placing US nuclear weapons back in South Korea may be the best end point to reduce risks.
Pyongyang responded to the new sanctions with its customary bluster against South Korea, military demonstrations and leadership visits to frontline forces. More ominously it added cancellation of the armistice agreement that ended the Korean War, cut communication links with South Korea coupled with the nuclear threats against the US.
At other times Washington might have treated North Korea's rhetoric as so much puffing. But with both Pyongyang's nuclear and long-range missile programme advancing, President Barack Obama said that although the North "probably can't" make good on its threat to hit the US, "we don't like margin of error". The result? The president signed off on Pentagon plans to add an additional 14 missiles in Alaska by 2017 to the 30 that possibly could - the programme's reliability remains in question - defend the country against such a strike.
While it may be many years before the North can hit the US homeland with the required long-range nuclear-armed ballistic missile, South Korea does not have that luxury. Pyongyang's arsenal today contains shorter-range rockets capable of striking South Korea. Presumably Kim's scientists are working hard to develop a warhead that could fit on to such delivery systems. In the interim the South must evaluate whether a defence strategy geared toward a conventional-armed adversary is capable of dealing with an emerging nuclear one.
Polling in South Korea suggests popular doubt. Even before North Korea's nuclear weapons test, two-thirds of interviewees stated security requires a nuclear component - either American nuclear weapons on South Korean soil or an indigenous South Korean arsenal. In the current pinch, the latter could come from plutonium harvested from the South's nuclear spent fuel, a byproduct of the country's large nuclear-power programme. Contrary to conventional wisdom, civil reactors can serve as plutonium mines for weapons-usable material. Extracting the plutonium would require a reprocessing plant that South Korea does not have today. It also does not have a bomb design. Weapon manufacture could take two years. However, given Washington's unalterable determination to halt new nuclear-weapons proliferation, whether by friend or foe, such a step would meet intense American pushback, jeopardising the alliance as Seoul experienced when it last explored the option in 1974.
Rather than steer a separate course, Washington counsels South Korea that the security relationship remains strong buttressed by some 28,000 American troops in the South in addition to the offshore US nuclear umbrella housed in Guam, Okinawa and at sea, available to deter and fight if needed. To demonstrate the commitment, with aircraft launched from Guam and Missouri, the US Air Force conducted a nuclear-capable B-52 and B-2 flyover of the South in recent military exercises that included nuclear-armed warships. At the conclusion of the naval exercises, South Korean officials reported the vessels would "stay a while" to impress Pyongyang about Washington's nuclear commitment.
"A while" does not make for a permanent presence. History suggests that a layered nuclear deployment may offer more impact and reassurance, with the location of US nuclear weapons both in and out of the European theatre during the Cold War being a prime example.
That same policy applied to South Korea during the Cold War. From 1958 to 1991, the US housed 11 different nuclear weapons at different times in the South. At the peak, the arsenal included nearly 1,000 munitions designed for two purposes: one to target the Soviet Union and China in addition to North Korea; and the second to substitute for costly ground forces. With the collapse of the Soviet Union, Washington withdrew the arsenal. Well before, offshore nuclear weapons already had begun to compensate for earlier drawdowns.
The 1991 elimination laid the foundation for the February 1992 North-South agreement to denuclearise the peninsula. Unfortunately the ambition was short-lived, crumbling by year's end with Pyongyang's failure to cooperate with International Atomic Energy Agency investigators. Although, in time, some South Korean politicians called for the return of US weapons - gaining traction when in 2010 Defence Minister Kim Tae-Young told a parliamentary committee that the option deserved review - the government backpedalled, holding that its fidelity to denuclearisation would rub off on the North.
Such denuclearisation was not to be. North Korea's recent test stimulated yet more debate in Seoul. In Washington, even before Pyongyang's recent test, the House of Representatives Armed Services Committee formally called upon the Pentagon to review the option of an American nuclear presence in the South.
Such an appraisal must weigh alternatives and objections against the acute vulnerabilities South Korea could confront without a US nuclear presence and the fact that no missile-defence system can perform to perfection. Absent the return of nuclear weapons, South Korea will be open to North Korean nuclear intimidation and more risk-taking dismissive of the credibility of Washington's offshore nuclear forces. The absence could encourage Pyongyang to pursue military acts and dare Seoul: "Respond and look what we have." In the normal course of tensions, North Korea's arsenal could bully.
A return of nuclear weapons to South Korea will no doubt butt against the argument that they'll impede the diplomatic effort to reverse Pyongyang's nuclear programme. However, history has spoken: every understanding to constrain North Korea - the Nuclear Non-proliferation Treaty, the 1992 Peninsula Denuclearisation Accord, the 1994 Agreed Framework, the 2005 Six-Party Talks agreement to end the programme - has failed along with the North's 2012 consent to suspend nuclear and missile tests in exchange for Washington's food aid.
Rather than hope for a North Korean non-proliferation epiphany, South Korea must better prepare to live with its disturbing neighbour while conveying the emphatic message that the Kim regime will gain no military or political advantage. The return of American nuclear weapons to South Korea would be the strongest statement the US can make to buttress the position.
Bennett Ramberg served in the Bureau of Politico-Military Affairs in the US Department of State during the George H.W. Bush administration. He is the author of "Nuclear Power Plants as Weapons for the Enemy."
Yale Centre for the study of globalisation.