This year, an American nuclear submarine docked at a Korean port for the second time. This results from the Washington Declaration, an agreement between ROK president Yoon Suk Yeol and U.S. president Joe Biden. Struck in April, the compact reassures Seoul of the continuing coverage of Washington’s nuclear umbrella, calming national fervor in support of a Korean nuclear program.
But despite the submarine’s “strong signal,” it doesn’t solve the underlying issue, said Dr. Cheong Seong-Chang, Director of the Center for North Korean Studies at the Sejong Institute, when I interviewed him in Seoul in late June. Cheong has been one of the leading scholars advocating for Korea’s indigenous nuclear development, and he thinks the need now is still as serious as ever.
According to Cheong, South Korea faces significant threats. It’s not just North Korea, which has recently tested solid fuel rockets and displayed a miniature nuclear warhead that could fit on short-range ballistic missiles aimed at South Korea and Japan. China and Russia are also nuclear-armed potential adversaries with whom South Korea’s relations are worsening. China's nuclear stockpile will rise to 1,500 warheads in the next decade.
“South Korea is mostly concerned about North Korea’s nuclear program,” Cheong said, “but China’s nuclear threat is also growing.”
Cheong envisions a world where South Korea can provide nuclear deterrence, free from American constraints or unreliability.
He’s not the only one. Surveys earlier this year showed 70 percent or more of Koreans think South Korea needs its own nuclear weapons program. Parsing survey data is always tricky. There’s often a difference between what people might say in response to a hypothetical question and how people would think and act in reality. Another survey conducted in June found that 49.5 percent of Koreans prefer having U.S. troops provide deterrence, versus 33.8 percent prefer having their own South Korean nuclear program. But Cheong argues that a ROK nuclear program need not be the end of the alliance. In fact, it could strengthen the U.S.-ROK alliance in the next 70 years.
“Instead of the U.S. countering Chinese influence alone, if the U.S., Korea, and Japan and work together, it will be positive,” he said. “If South Korea has nuclear weapons, the U.S. will not have to focus as much attention on North Korea.”
There is no reason why an already solid bilateral relationship should sour because Korea possesses its own deterrent. Instead, Korea’s indigenous nuclearization would allow both sides to engage with each other on an equal basis.
“I believe that in the current structure of the alliance, the ROK relies excessively on the U.S.,” Cheong said. He pointed to examples of the United States pressuring South Korea to restrain itself following North Korean provocations, such as the aftermath of the 2010 bombardment of Yeongpyeong.
The North Korean attack on the island off the coast of Incheon killed two ROK soldiers and three civilians. According to Defense Secretary Robert Gates’ memoir, the Obama administration convinced former President Roh Moo Hyun to hold off a “disproportionately aggressive” response.
President Yoon also appears to be highly deferential to the United States. Cheong does not think he will push for nuclear development as long as he and Biden are both in office.
However, South Korean nuclear armament would make the region more secure, Cheong argues. The current equilibrium is unbalanced on multiple levels. North Korea possesses a nuclear advantage, while South Korea maintains a conventional weapon advantage. Cheong paints a scenario where inadvertent weapons discharge from North Korea could lead to a spiral of escalation. In such a case, North Korea, knowing it could not defeat the ROK with conventional weapons, would resort to tactical nuclear weapons. This scenario would be unthinkable if South Korea were similarly armed.
In geopolitical conflicts between two nuclear-armed nations, like the USSR and the U.S. or India and Pakistan, the two countries did not engage in direct armed warfare. Mutually Assured Destruction works.
Cheong does not think the presence of U.S. troops in the South would be an unshakable deterrent: “If the U.S. military bases are not attacked, it would be hard for the U.S. to respond.”
It is unclear what the U.S. might do, but skepticism of U.S. support is prevalent amongst a large proportion of the Korean population. A 2023 Hankook Ilbo survey found that only 36.7 percent of South Koreans think the U.S. would support the ROK “unconditionally” in a conflict with the North.
The prospect of American support over the next few decades is even more uncertain. American politics has become unstable and unpredictable. Isolationist rhetoric is popular. Donald Trump, who toyed with withdrawing U.S. troops during his 2016 campaign and presidency, is running for office again.
“The age in which the U.S. can manage security in the whole world is over,” Cheong said.
Even some Americans agree with Cheong’s argument. Doug Bandow, a scholar at the Cato Institute, has written, “Washington will have to decide whether it is willing to risk national destruction to continue protecting the ROK. If not, then Washington should contemplate the currently unthinkable—a South Korean nuclear weapon.”
Nonetheless, many Koreans consider the idea of nuclear proliferation reckless and destabilizing. Yonsei University professor Moon Chung-In called the idea a “lose-lose-lose” proposition in an op-ed in the Hankyoreh. He wrote that it would lead to a nuclear arms race in Northeast Asia and harsh sanctions on South Korea, which would have a “fatal impact on our survival, prosperity, and prestige.”
This argument isn’t going away anytime soon. As long as South Korea feels insecure, there will be calls for nuclearization and warnings against it.
For his part, Dr. Cheong is not calling for an immediate push toward a bomb. He supports taking measures to prepare for the possibility, such as lobbying for greater nuclear fuel reprocessing capability.
“I’m not arguing that we should start arming ourselves now,” he said. “But as long as the security situation gets worse, it is inevitable that South Korea will need to develop nuclear weapons.”