With Yoon Suk-yeol at helm, South Korea is set for a foreign policy reset

When South Korean president-elect Yoon Suk-yeol begins his term on May 10, Seoul is expected to make significant changes in its foreign policy, taking a more confrontational approach toward North Korea and shifting to a tougher line with China.

The former prosecutor-general has also signaled that he intends to bolster his country’s alliance with Washington and strengthen South Korea’s own military capabilities to “completely deter any provocation” from Pyongyang.

“I’ll rebuild the South Korea-U.S. alliance. I’ll (make) it a strategic comprehensive alliance while sharing key values like a liberal democracy, a market economy, and human rights,” the conservative politician from the People Power Party said just hours after his narrow electoral win.

Yoon has already taken initial steps in this direction. South Korean media reported earlier this month that the 61-year-old dispatched delegates to discuss with U.S. national security adviser Jake Sullivan the potential redeployment to South Korea of U.S. strategic assets, which include nuclear weapons as well as platforms such as long-range bombers, submarines and aircraft carriers.

Moreover, Yoon sent a seven-member delegation to Japan in April for meetings with Prime Minister Fumio Kishida and other top officials, carrying a letter outlining his will for "new relations with Japan." During a meeting at the Prime Minister’s Office, Kishida underscored the urgent need to improve bilateral ties and resolve underlying issues such as the wartime labor of Koreans.

Meanwhile, the president-elect will have an opportunity to personally strengthen Seoul’s alliance with Washington and discuss the issue of strategic weapons during his first summit with U.S. President Joe Biden on May 21.

Growing support for nukes

Washington had stationed nuclear weapons in South Korea from 1958 but withdrew them in 1991 as part of an agreement with Moscow to end the foreign deployment of tactical or “battlefield” nuclear weapons, such as nuclear artillery shells.

However, conservative politicians in South Korea, including Yoon, have in recent years renewed calls for a redeployment of such assets amid Pyongyang’s repeated military provocations and its growing arsenal of nuclear-capable missiles.

Yoon’s latest request seems to reflect the growing public opinion in the country, with recent polls showing robust local support for positioning nuclear weapons on South Korean soil.

According to a December 2021 poll conducted by Hankook Research, 56% of respondents said they would back a redeployment of U.S. nuclear weapons, with an even higher percentage of South Koreans (71%) expressing support for their country developing its own nuclear weapons.

When asked to choose between these two options, the public said it would prefer an independent arsenal (67%) over U.S. deployment (9%). This is mainly due to the vulnerable position South Korea would be in without U.S. military support and the commonly held view that Pyongyang is unlikely to give up its nuclear arsenal.

South Korea, which has a mutual defense treaty with the United States, comes under the protection of the U.S. nuclear umbrella. Although the country initially abandoned its nuclear weapons ambitions in the 1970s, the acquisition of such assets has become a mainstream feature of the national security discourse in recent years.

The argument is that such weapons are needed to not only strengthen deterrence but also maintain a balance of power with North Korea, and possibly even make North Korean leader Kim Jong Un reevaluate his threats.

The U.S. perspective

Washington's view of a nuclear-armed South Korea has been unambiguous. Asked about the matter in September 2021, U.S. Deputy Assistant Secretary of State Mark Lambert ruled out a redeployment of such assets, saying that U.S. policy “would not support” such a move.

Bruce Bennett, a senior defense analyst at the U.S.-based RAND Corporation think tank, argues that Washington’s position is unlikely to change much anytime soon.

While basing a U.S. aircraft carrier in South Korea would be possible, it would also be “an extremely expensive move, which the U.S. Navy has been reluctant to make and which I doubt Seoul will want to significantly subsidize,” he says.

Moreover, stationing B-52 or B-1 bombers would not only be expensive but would also make the aircraft “excessively vulnerable,” given the small number of South Korean airfields such aircraft can operate from, he said.

“From my interactions with senior North Korean escapees, I think that President-elect Yoon should be looking instead for weapons and platforms that would intimidate North Korea.”

Such an approach would include more advanced military platforms such as F-35 fighter aircraft, Aegis-equipped warships, and Terminal High Altitude Area Defence (THAAD) ballistic missile defense systems as well as U.S intermediate-range ballistic missiles (some hypersonic), the latter of which would be deployed once their development has been completed.

An exception to the rule?

That said, Bennett pointed out that the U.S. could eventually make an exception for the B61-12, which is the latest variant of the B61 family of air-launched nuclear gravity bombs. These tactical nuclear weapons are designed to destroy deep underground facilities such as the command control facilities where the North Korean leadership would likely seek shelter in the event of a nuclear confrontation.

The analyst argues the U.S. and South Korea should set a threshold number for North Korean nuclear weapons they would tolerate before deploying such bombs to the Korean Peninsula.

“The threat of deploying a modest number of B61-12s might be enough to convince ... Kim Jong Un to moderate his production of nuclear weapons or to accept a nuclear weapon production freeze,” he said, adding that this could also prompt Beijing to try to prevent Pyongyang from bolstering its nuclear arsenal.

The Biden administration should make it clear that North Korea has a choice: It can either stop its nuclear weapon production or face U.S. nuclear weapons back on the Korean Peninsula, Bennett says.

‘Peace through strength’

Yoon’s plans to align South Korea’s foreign and defense policies more closely with those of Washington, strengthen ties with Japan and Southeast Asia and possibly even join “the Quad” grouping of nations, will certainly be welcomed by the Biden administration.

However, such policies also mean that the transition of power from President Moon-Jae-in to Yoon is likely to strain Seoul’s ties with Pyongyang and Beijing.

“Unlike Moon, who sought to peacefully resolve the North Korean nuclear issue using a two-track approach of sanctions along with pressure and dialogue, President-elect Yoon does not see the inter-Korean dialogue as an effective means to deter North Korea’s missile and nuclear threats,” says Mitch Shin, from the Institute for Security & Development Policy (ISDP) in Sweden.

“Yoon seems to believe that the North Korean leadership will not return to the negotiating table anytime soon. He believes in ‘peace through strength,’ which is why deepening the U.S.-South Korean military alliance and deploying advanced weapon systems on South Korean soil are his first priorities, not engaging in talks with Pyongyang,” Shin said.

While the president-elect has kept the door open to dialogue and negotiations with Pyongyang, “the spring days of the inter-Korean relations are over,” he noted.

“Yoon has downplayed Moon’s efforts to engage in talks with Pyongyang and, based on his pledges to join the Quad, his defense policies explicitly differ from those of the outgoing president who has hesitated to join the U.S.-led anti-China security groups or coalitions,” Shin said.

China and ‘the three noes’

As for relations with China, Beijing is likely to object to Seoul’s tilt toward Washington as well as to Yoon’s plan to deploy additional THAAD batteries in response to North Korea’s missile development, said Scott Snyder, director of the U.S.-Korea Policy program at the New York-based Council of Foreign Relations. Beijing has repeatedly expressed strong opposition to THAAD, stating that the system poses a threat to its own security.

Snyder also believes Beijing would take a dim view of Yoon’s openness to an enhanced trilateral security relationship with the U.S. and Japan based on the goal of restoring Japan-South Korea relations.

Such moves would “step over Chinese red lines contained in the “three noes” pledge the Moon administration made to China — to not procure additional missile defenses, integrate South Korean missile defense capabilities with those of Japan and America or form a trilateral U.S.-Japan-South Korea alliance,” he said.

Yoon, who has raised the possibility of launching a pre-emptive strike against the North to counter an impending missile threat, has defended the planned expansion of THAAD as South Korea’s sovereign right to defend itself. Moreover, he emphasized that his country should never be forced to choose between China, its top trading partner, and the U.S., its ally and most important security partner.

As part of its policy alignment with Washington, the Yoon administration will probably embrace the U.S. Indo-Pacific strategy and cooperate with like-minded partners in the region. This would further complicate relations with Beijing, whose assistance Seoul would need to achieve North Korean denuclearization.

It is not clear how the Yoon administration will try and solve these diplomatic and security issues with China, but analysts agree that any U.S. deployment of tactical nuclear weapons to the Korean Peninsula will almost certainly trigger a strong response from both Beijing and Pyongyang.

Carrot and stick

Given the high stakes and the possible intensification of the regional arms race, experts such as Bennett believe Yoon should implement a carrot and stick strategy toward North Korea. “If he only applies pressure (stick), the North is likely to escalate and create many crises on the peninsula. But by also offering a route to improved relationships (carrot), he has a better chance of sustaining South Korean independence and regional peace,” he said.

Meanwhile, U.S.-South Korean ties are expected to significantly improve under a Yoon presidency, with the two sides aiming to conduct more and larger joint military exercises and expand their defense technology cooperation programs.

At the same time, there is still much work to be done. For instance, Shin says that growing calls within South Korea for the local development of nuclear weapons will be one of the greatest challenges to deepening ties with the U.S.

Moreover, given the failures of previous North Korea policies and Pyongyang’s attempts to drive a wedge between Seoul and Washington, the two allies need to devise new strategies.

The U.S. and South Korea cannot carry on with the policy of strategic patience the White House formally renounced a year ago but has apparently continued to practice, said Bennett. “That must change and replacing it will require some creativity and real work.”