The Big Reason Why South Korea Cannot Go Nuclear

As the United States is growing less dependable as an ally under the second Donald Trump administration, many countries in the Western bloc are rushing to strengthen their own defense capabilities. NATO member states are a prime example.

In South Korea, there is growing support for possessing nuclear weapons. In the face of Trump’s cold-eyed, transactional approach toward Ukraine, many question whether the U.S. would be willing to put Washington at risk to defend Seoul if a nuclear-armed North Korea were to attack South Korea.

Furthermore, Trump has referred to North Korea as a “nuclear power” twice already this year, in January and March, although successive U.S. administrations have never officially recognized the communist regime as a nuclear-weapon state (so far).

According to a public opinion poll conducted by public broadcaster KBS in late January this year, when asked how they would feel about South Korea possessing nuclear weapons if North Korea is recognized as a nuclear power by the international community, 74 percent of South Koreans answered “in favor,” far exceeding the 20 percent who answered “against.”

In fact, arguments for South Korea to acquire its own nuclear weapons have been heating up since the Yoon Suk-yeol administration took office in May 2022. 

Yoon himself said on January 11, 2023, “As the [North Korean] nuclear issue becomes more serious, South Korea could have tactical nuclear weapons deployed or secure its own nuclear weapons.”

“If the North Korean nuclear threat becomes more serious… we will be able to acquire [nuclear weapons] quickly thanks to our science and technological capabilities,” Yoon added.

The remarks by the incumbent South Korean president suggesting the possibility of acquiring nuclear weapons caused a great stir both at home and abroad. The next day, the U.S. State Department, then under the Joe Biden administration, immediately expressed caution, stating that “denuclearization is the core of the ROK-U.S. alliance.” (ROK is an abbreviation of South Korea’s formal name, the Republic of Korea.)

Contrary to Yoon’s words, military experts in South Korea think it is technically impossible for Seoul to be armed with nuclear weapons because the nation is too small to have a nuclear test site. South Korea’s land area is about the size of the U.S. state of Kentucky.

Asked by The Diplomat if there is any potential nuclear test site in South Korea, Kim Young-jun, a professor at the Korean National Defense University in Nonsan City, said, “It is difficult to find a possible site for a nuclear test site for nuclear armament due to the expected opposition from local communities.”

“There is not even any place to dispose of nuclear fuel waste,” Kim pointed out.

“Public opinion supporting nuclear armament is meaningless because it is a simple survey conducted without considering these factors,” he continued. “Nuclear tests are not possible [in South Korea], and the approval ratings of political leaders who would pursue such a project cannot be guaranteed.”

Kim Dae-young, a military expert who used to work at the Korea Research Institute for National Strategy, echoed the same view.

“There is a lot of talk in the public sphere regarding South Korea's nuclear weapons development, but no one talks about the detailed conditions as such,” he said.

“Underground nuclear testing is possible in the mountainous Gangwon Province, but in the difficult political environment, no site has been found for nuclear fuel waste, so finding a nuclear test site also would not be difficult,” Kim Dae-young said.

“Conservative groups in South Korea are arguing for independent nuclear weapons development as a political savior without engaging in thorough debate,” he concluded.

The U.S. Department of Energy, which manages nuclear weapons, has designated South Korea as a “sensitive country” that requires attention in terms of nuclear non-proliferation and security. The Biden administration made the decision in January, just before Trump took office. The department did not disclose the reasons for the designation, but more than a few media outlets have reported that Washington may have been concerned about the growing calls for nuclear armament in Seoul as North Korea accelerates its nuclear and missile development.

What one has to remember is that North Korea is not the only country rapidly developing its nuclear program in East Asia; China is doing the same or even more. Russia’s President Vladimir Putin has elevated his nuclear threats since the start of the war against Ukraine in February 2022. With South Korean politics becoming unstable and Washington politics moving toward isolationism, attention is focused on how the debate over Seoul’s nuclear program will go on.