Report

Talk of a Nuclear Deterrent in South Korea

North Korea’s resumed activity at Yongbyon has reawakened calls for Seoul to go nuclear.

By , a freelance journalist based in Seoul who writes about geopolitics.
South Koreans walk past replicas of missiles at the Korean War Memorial.
South Koreans walk past replicas of a North Korean Scud-B missile and South Korean Nike missile at the Korean War Memorial in Seoul on Feb. 28, 2019. Chung Sung-Jun/Getty Images

SEOUL—Recent resumption of activity at North Korea’s Yongbyon nuclear complex, which is suspected of producing the plutonium needed for the country’s nuclear weapons, has fueled existing convictions among some conservative South Korean politicians that Pyongyang will never agree to give up its nukes so Seoul needs a nuclear deterrent of its own.

The issue has stormed into the early days of the upcoming presidential election, with primary candidates openly pushing for South Korea to host nuclear weapons. Yoo Seong-min, a former lawmaker and primary candidate for the People Power Party, said he would “persuade the U.S. government to sign a nuclear-sharing agreement” with Seoul if he became president. Such an agreement would again allow the deployment of tactical and nonstrategic nuclear weapons on South Korean soil for the first time since the end of the Cold War. Another conservative contender, Hong Joon-pyo, has also argued that a nuclear-sharing agreement is needed lest South Korea end up “slaves to North Korea’s nuclear weapons.”

For some in South Korea, it’s not just about hosting U.S. weapons but also about developing their own. Lee Jong-kul, a representative from the Liberal Party, has said South Korea should “choose tactical nuclear weapons as the last negotiating card” against North Korea. In 2017, a conservative group, the Korean Patriotic Citizens’ Union, organized protests that included chants like “South Korea should immediately begin to arm itself with nuclear weapons.” Nuclear boosterism has grown so much that the leading primary candidate for the Liberal Party, Lee Jae-myung, decried it as “dangerous populism.”

SEOUL—Recent resumption of activity at North Korea’s Yongbyon nuclear complex, which is suspected of producing the plutonium needed for the country’s nuclear weapons, has fueled existing convictions among some conservative South Korean politicians that Pyongyang will never agree to give up its nukes so Seoul needs a nuclear deterrent of its own.

The issue has stormed into the early days of the upcoming presidential election, with primary candidates openly pushing for South Korea to host nuclear weapons. Yoo Seong-min, a former lawmaker and primary candidate for the People Power Party, said he would “persuade the U.S. government to sign a nuclear-sharing agreement” with Seoul if he became president. Such an agreement would again allow the deployment of tactical and nonstrategic nuclear weapons on South Korean soil for the first time since the end of the Cold War. Another conservative contender, Hong Joon-pyo, has also argued that a nuclear-sharing agreement is needed lest South Korea end up “slaves to North Korea’s nuclear weapons.”

For some in South Korea, it’s not just about hosting U.S. weapons but also about developing their own. Lee Jong-kul, a representative from the Liberal Party, has said South Korea should “choose tactical nuclear weapons as the last negotiating card” against North Korea. In 2017, a conservative group, the Korean Patriotic Citizens’ Union, organized protests that included chants like “South Korea should immediately begin to arm itself with nuclear weapons.” Nuclear boosterism has grown so much that the leading primary candidate for the Liberal Party, Lee Jae-myung, decried it as “dangerous populism.”

South Korea, which suffered an invasion by its northern neighbor in 1950, is regularly taunted by Pyongyang’s nuclear capabilities, tests, and parades of increasingly capable missiles.

“The idea of nuclear weapons in South Korea, in contrast to Japan, has never been fringe. The argument is something like: If North Korea has it, we should have it too,” said Jeffrey Lewis, director of the East Asia Nonproliferation Program at the Middlebury Institute of International Studies at Monterey.

According to polls, almost half of all South Koreans surveyed support the development of their own nuclear weapons to deter North Korea’s threat. The urge to unfurl their own nuclear umbrella has grown in recent years due to both Pyongyang’s fissile and missile advances and after four years of former U.S. President Donald Trump disparaging the Korean alliance and urging the country to develop its own nuclear shield.

But it’s not just politicians and polls. South Korea is the latest member of an exclusive club: countries that have successfully fired submarine-launched ballistic missiles (SLBMs). Seven other countries have done that, but they all have nuclear warheads to stick on top. So what are Seoul’s ambitions? 

South Korea “is the only country to develop SLBMs without first developing nuclear weapons, so it makes one wonder,” said Vipin Narang, a professor of nuclear security and political science at the Massachusetts Institute of Technology.

SLBMs are hidden underwater, so they offer survivability that could ensure South Korea can hit back against a first strike. But hit back with what?

“Even with a heavy conventional warhead or multiple warheads on each SLBM, does six tubes on a submarine really provide a credible conventional retaliatory capability if all of South Korea’s land-based missiles were wiped out?” Narang asked.

It’s not the only nuke-adjacent technology being advanced. With the removal of the country’s range cap on its missiles, South Korea is pushing for missiles that can carry bigger payloads for longer distances. Those “would be good delivery vehicles” if Seoul ever thought about developing nuclear weapons, Narang said.

The problem is nuclear weapons would not actually deliver security for South Korea. Pyongyang has an arsenal of its own and knows it can poke and prod—whether through cyberattacks or other conventional provocations—with little fear.

“In terms of South Korea’s security, nuclear weapons do very little,” Lewis said. “A nuclear-armed North Korea can be much more aggressive in terms of conventional provocations because [North Korean leader] Kim Jong Un knows he is safe from being invaded by the United States or South Korea. South Korean nuclear weapons don’t solve this problem.”

It’s much like the problem facing Israel, which is widely believed to have its own nuclear capability yet has fought vehemently for years to constrain Iran’s ability to enrich enough uranium to build a bomb.

“Israel has nuclear weapons but is terrified of Iran getting them. Why don’t the Israelis believe deterrence will protect them? Because they are worried that a nuclear-armed Iran will be much more aggressive in terms of using proxies to attack them,” Lewis said. “It’s a very similar problem for South Korea.”

In addition to not delivering deterrence, South Korean nuclear weapons could end up blowing up the Korean economy. It’s one of the most trade-dependent countries on Earth, with trade making up about 70 percent of the country’s GDP; those export industries are dependent on its status as a proliferation-limiting state. A particular concern could be the country’s successful civilian nuclear energy program. South Korea is halfway through a 20-year plan to export 80 nuclear reactors worth $400 billion—deals that could be jeopardized if South Korea opts for proliferation. 

“South Korea is very much a trade-dependent country, basically an economy based on the international economy, and the repercussions from developing nuclear weapons will damage this,” said Yim Man-sung, director of the Nuclear Nonproliferation Education and Research Center at the Korea Advanced Institute of Science and Technology in Seoul. 

South Korea, a signatory to the nuclear nonproliferation treaty, could withdraw from the accord. But that would create a cascade of legal liabilities, especially for the multibillion-dollar exports of civilian nuclear technology. And that, once realized, could take the wind out of the South Korean public’s push for nukes of their own.

“Initially, when people know nothing about the implications, they may say, ‘oh, we should develop nuclear weapons.’ But once they realize the implications, repercussions of that decision, most of them say no,” Yim said.

Morten Soendergaard Larsen is a freelance journalist based in Seoul who writes about geopolitics.

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