Ahead of his inauguration as South Korea’s president on Tuesday, Yoon Suk-yeol promised he would “dramatically strengthen” his nation’s defences against the rapidly developing nuclear forces of North Korea.
The conservative president’s campaign pledge highlighted an intensifying debate in the country whether to push for a return of US nuclear weapons to the Korean peninsula — and even whether South Korea should seek to develop its own nuclear deterrent.
Yoon used his inauguration address to offer “an audacious plan that will vastly strengthen North Korea’s economy” if Pyongyang committed to denuclearisation. But experts believe it is highly unlikely that North Korean leader Kim Jong Un will give up its arsenal.
Pyongyang has carried out a flurry of ballistic missile tests since September and the US has warned North Korea could conduct its first nuclear test since 2017 this month. South Korean officials have also been spooked by Russia’s use of nuclear threats to deter western intervention in Ukraine.
“The big thing that has changed is what Russia has done in Ukraine,” said Karl Friedhoff, a Korea expert at the Chicago Council on Global Affairs.
“The Korean security establishment never quite took the possibility of North Korean nuclear coercion entirely seriously, but seeing how Russia has been able to threaten potential nuclear use from the very beginning of the war has opened people’s eyes,” Friedhoff said.
South Korea’s strategy for using its conventional military to deter Pyongyang relies on capabilities it calls the “Three Ks”. These are pre-emptive missile strikes, dubbed “Kill Chain”, to take out launch sites if a nuclear attack is judged imminent, with “Korea Air and Missile Defence” to destroy incoming projectiles and “Korea Massive Punishment and Retaliation” to hit back at Pyongyang.
Under outgoing president Moon Jae-in, Seoul invested heavily in fighter aircraft, submarine-launched ballistic missiles and military spy satellites. South Korea is also developing its own missile defence system modelled on Israel’s Iron Dome.
But analysts said South Korea’s ability to rely on its conventional military superiority to deter attacks was being eroded, increasing its reliance on the nuclear umbrella provided by the US, Seoul’s closest security ally.
“North Korea’s development of solid-fuel missiles that can be fired at a moment’s notice undermines the Kill Chain, its manoeuvrable missiles challenge South Korea’s missile defences, while the threat of potential early nuclear use poses a threat to the whole package,” said S Paul Choi, founder of Seoul-based political risk advisory StratWays Group.
“Korean security officials have long been uncomfortable about this, but the problem is getting more acute, leading more people to question our reliance on America’s extended deterrent,” Choi said.
The US removed all its nuclear warheads from South Korea in 1991, but Chun In-bum, a retired lieutenant general and former commander of the South Korean special forces, said US tactical nuclear weapons should be deployed to the peninsula in response to the threat posed by those of North Korea.
At a military parade last month, Kim signalled his willingness to engage in nuclear coercion in defence of his country’s “fundamental interests”, declaring that his nuclear arsenal had a “secondary mission” that went beyond that of preventing war.
Chun said tactical nuclear forces should be stationed in South Korea that could “deliver a response within 1-3 minutes, not 45 minutes or a couple of hours”.
“It is only when both sides place each other in such a dangerous situation that they will think about getting rid of such weapons,” he said. “It’s cold war logic, but that’s where we are right now. The North Koreans are just not taking us seriously.”
Jeongmin Kim, lead analyst at Seoul-based information service Korea Pro, said many members of the incoming Yoon administration shared Chun’s desire to see US nuclear weapons deployed on South Korean territory.
“The Korean conservatives have signalled not only that they want more nuclear assets made available to defend the Korean peninsula, but that they want greater assurances as to how the US might respond in an emergency situation,” said Kim. “They want to have more of a say, and they want to have greater understanding of US thinking on nuclear use.”
She added Yoon would be more willing to project strength than his progressive predecessor, whose hopes of securing his political legacy as a peacemaker were dashed by North Korean intransigence.
“The difference between the two administrations will be one of tone, rather than actual military readiness,” said Kim. “Whereas Moon Jae-in used to prioritise dialogue and tension management, Yoon will prioritise signalling to South Korean citizens that their deterrence is effective.”
Some analysts warned a more confrontational line could be counter-productive.
“Doubling down on deterrence, economic isolation and the threat of military force will only deepen instability on the peninsula at a time when North Korea is ratcheting up tension,” said Jessica Lee, a fellow at the Quincy Institute for Responsible Statecraft in Washington.
Recent polling by the Chicago Council on Global Affairs suggested continuing public support in South Korea for the country to acquire its own nuclear weapons, with 71 per cent of those surveyed in favour.
Christopher Green, senior consultant for the International Crisis Group, said that just as North Korea started developing nuclear weapons in the late 1970s in response to perceived military vulnerability, South Korea could be reaching the conclusion it needs its own nuclear forces.
“The US has an awful lot of leverage by which to restrain South Korean ambitions in that regard,” said Green. “Washington could theoretically acquiesce if it saw North Korea as otherwise undeterrable, but I don’t foresee that happening anytime soon.”
But Chun said Seoul should not assume it will be able to rely on the external guarantees of a distant US forever.
“Either American extended nuclear deterrence is formidable and credible, or South Korea acquires its own nuclear weapons,” Chun said. “I have never doubted an American soldier. But I would be foolish to place my nation’s security in the hands of an American politician.”