South Korea Revives Nuclear Debate as Tensions With the North Rise

SEOUL—Rising tensions on the Korean Peninsula and Pyongyang’s spree of weapons tests are fueling a debate in South Korea over the deployment and development of nuclear weapons as a deterrent.

South Korean President Yoon Suk-yeol and some ruling-party lawmakers are pushing for Washington to allow Seoul to be more involved in the management of nuclear weapons, including planning and joint exercises. Some lawmakers have even called for the U.S. to deploy tactical nuclear weapons on the Korean Peninsula again or for South Korea to develop its own nuclear weapons.

South Korea is protected under what is known as the nuclear umbrella—an agreement that says the U.S. will use its nuclear weapons to defend its ally. But Mr. Yoon has said that is no longer sufficient to reassure the South Korean public, in the face of an increasingly aggressive and militarily capable North Korea.

Washington has rejected calls to redeploy nuclear weapons on the Korean Peninsula, while reaffirming that the U.S.is committed to defending South Korea. Opponents to South Korea developing its own nuclear weapons say it would violate the Nonproliferation Treaty and create a greater risk for nuclear war.

Experts on North Korea say any further nuclear buildup could inflame tensions with Pyongyang and undermine Washington’s goal of completely denuclearizing the Korean Peninsula.

“Adding new weapons systems to the Korean Peninsula destabilizes the situation and gives North Korea more reason to accelerate its nuclear program,” said Ken Gause, an expert on North Korean leadership at CNA, a nonprofit research organization.


On Monday, Mr. Yoon told a South Korean newspaper that Seoul and Washington were discussing conducting joint exercises using U.S. nuclear assets.

President Biden denied that the allies were holding talks on joint nuclear drills. On Tuesday, White House press secretary Karine Jean-Pierre said Messrs. Biden and Yoon had instructed their governments to enhance joint defense readiness based on U.S. extended deterrence in response to North Korea’s threat, adding that the two nations weren’t discussing joint nuclear exercises because South Korea was a non-nuclear-weapons state.


Support for South Korea to develop its own nuclear weapons has similarly risen at times of increased tension between the two countries. In 2018, when North Korean leader Kim Jong Un engaged in summits with Mr. Yoon’s predecessor, Moon Jae-in, public support in South Korea for the acquisition and development of nuclear weapons stood at about 55%, according to polls by the Chicago Council on Global Affairs.

By 2022, support had risen to 70%, with negotiations stalled and North Korea’s weapons development becoming more menacing. “South Koreans know they are living in a very unforgiving region so perhaps taking security into their own hands is seen as a logical next step,” said Karl Friedhoff, a fellow in public opinion and Asia policy at the Chicago Council on Global Affairs.

Tensions have risen rapidly on the Korean Peninsula, as North Korea has accelerated its weapons testing and Mr. Yoon has taken a tougher line on Pyongyang than Mr. Moon. Pyongyang conducted a record number of missile launches last year, including an intercontinental ballistic missile and a submarine launched missile.

Officials in Washington and Seoul have said the country appears to be preparing for another nuclear test. The North Korean leader during a year-end party meeting pledged to exponentially increase his nuclear arsenal.
Last week, North Korea flew five drones over South Korean territory.

On Thursday, South Korea’s spy agency told lawmakers it couldn’t rule out the possibility that one of the drones had filmed the presidential office. A military official said a North Korean drone briefly entered the northern edge of the no-fly zone over the presidential office but it didn’t come close to security facilities.

Mr. Yoon said this week that he would consider suspending a 2018 pact between the countries that bars hostile acts in border areas if North Korea violated South Korean airspace again.

Pyongyang has violated the agreement 17 times, including by firing a missile close to South Korea’s territorial waters and firing artillery shells near the border, according to the presidential office.

The U.S. and South Korea have expanded their joint military drills, and the Yoon administration has pledged to share missile-warning data with the U.S. and Japan in real time.

Mr. Yoon has also pursued the strengthening of conventional defense and missile capabilities by acquiring submarine-launched ballistic missile capabilities and developing homegrown missile-interception systems.

But those advocating for the redeployment of nuclear weapons say that conventional capabilities are insufficient to prevent a war on the Korean Peninsula, and that the U.S. nuclear umbrella can’t be fully trusted.

“We can’t counter nuclear weapons with conventional weaponry, so there is no way but to acquire nuclear capabilities ourselves,” ruling-party lawmaker Kim Gi-hyeon, who has called for South Korea to develop its own nuclear weapons, said in October as he was running for the party’s chairmanship.

Some South Korean lawmakers have called for the U.S. to deploy nuclear weapons on the Korean Peninsula, possibly by permanently stationing nuclear-armed submarines or aircraft carriers in nearby waters.

Some have suggested a North Atlantic Treaty Organization-style arrangement in which South Koreans would be trained to deliver U.S. nuclear weapons in conflict. Washington has rejected those calls.

Opposition party lawmakers, who generally support dialogue with North Korea, have said bringing nuclear weapons back to the Korean Peninsula would undermine the country’s longstanding support for nuclear disarmament.
The country would lose legitimacy in its push for the denuclearization of North Korea, said Kim Byung-joo, a retired army general and lawmaker of the Democratic Party.

The U.S. and South Korea have faced limitations in countering North Korea’s threat other than strengthening deterrence and preparing for future negotiations, said former South Korean nuclear envoy Wi Sung-lac, especially as Russia and China vetoed additional United Nations sanctions following ICBMtests and dozens of short-range ballistic missile launches last year.

“The Yoon administration may pursue more involvement in deploying U.S. nuclear assets, but China and Russia will perceive greater U.S. presence on the Korean Peninsula as a significant threat, making it even more difficult to seek their support on resolving North Korea’s nuclear issue,” Mr. Wi said.

Despite the risks of a nuclear buildup on the Korean Peninsula, some members of the public say they are more open to South Korea developing its own nuclear weapons. Lee Han-sol, a 26-year-old college student, says he used to give little thought to South Korea acquiring its own weapons, when he saw the leaders of the two Koreas holding summits and agreeing to peaceful relations in 2018.

“My thoughts have changed a bit since finishing military service, where we’re taught to think of North Korea as the enemy, and the constant missile tests and talk of nuclear testing now have me thinking South Korea needs a better way to defend itself. Nuclear weapons could be one option,” Mr. Lee said.

Write to Dasl Yoon at dasl.yoon@wsj.com