US President Donald Trump meets Kim Jong-un at the Korean Demilitarized Zone, June 30, 2019. Credit: Public Domain.

There are two major variables that factor into South Korea’s calculus on starting a nuclear weapons program: the feasibility of North Korea abandoning its nuclear weapons voluntarily, and the guarantee of America’s extended deterrence in the event of the nuclear crisis on the peninsula. Both are trending in the wrong direction.

North Korea’s intermittent nuclear threats have increasingly weighed on the minds of the broader public in South Korea, and South Koreans have started to suspect that there’s no ray of hope left for the complete denuclearization of North Korea. “Denuclearization is the dying wish of Kim Il-sung, the founder of the regime,” South Koreans have heard countless North Koreans say. But the North’s assertion that the founder’s dying wish is still operative is at best disingenuous and at worst an outright lie. In hindsight, denuclearization was dead on arrival.

Unsurprisingly, a growing chorus of voices in South Korea has given up on the rosy fantasy of disarming Kim Jong-un and is instead calling for arming the “Land of the Morning Calm” with destructive nuclear weapons. A September 2017 Gallup poll found 60 percent of South Koreans support nuclear armament, while only 35 percent are opposed. Though the public is anxiously waiting to see if North Korea will strike a deal with the Trump administration, few remain optimistic.

While many decision makers still believe that the best course is to rely on the extended deterrence provided by the United States nuclear umbrella, a growing number are quietly contemplating the alternatives. During a recent speech at the Center for Strategic and International Studies in Washington, former South Korean Foreign Minister Song Min-soon said that “the Republic of Korea taking its own measures to create a nuclear balance on the peninsula” was a “widely touted” option. Such a statement is strong evidence of just how far moderate proponents of nonproliferation have shifted.

The reason for this shift is that today, South Koreans cast a much more doubtful eye toward the United States security guarantee than ever. In particular, more conservatives, who are traditionally reliably US-friendly, do not hide their uneasiness about President Trump. Many were offended when, at a rally earlier this year, Trump brought up the issue of the burden-sharing arrangement for US personnel in South Korea and mocked that, “[i]t was easier to get a billion dollars from South Korea than to get $114.13 from a rent-controlled apartment in Brooklyn.”

More offensive, though, is that Trump has conspicuously tolerated North Korean missile tests that directly threaten South Korea, which hosts the third-largest contingent of overseas US troops as well as a US anti-ballistic missile defense system and is one of the world’s biggest buyers of US arms. The more Trump brags about the letters from Kim Jong-un, the more he alienates an ally. Even moderate South Koreans see Trump’s approach to the alliance as extremely petty and bigoted. In sum, his flagrant disregard for the traditional alliance undermines the credibility of extended deterrence and has made South Koreans pessimistic about their continued dependence upon the United States.

Many Americans, even in the administration, know all of this. In September, US Special Representative for North Korea Stephen Biegun rhetorically asked, “at what point will voices in South Korea or Japan and elsewhere in Asia begin to ask if they need to be considering their own nuclear capabilities?” Unfortunately, though, little is being done to assuage South Korean concerns.

If these trends continue, a nuclear South Korea is a question of “when,” not “if.”

Of course, the path to a nuclear weapon would not be free of obstacles. South Korea, as the only country in the region that has never attacked any other neighboring countries, is a staunch defender of nonproliferation norms. Many pundits in academic and security policy circles as well as high ranking officials in government still fret about the feasibility of pursuing an independent nuclear deterrent. Few security analysts think it would be possible for any president to successfully pursue a such a politically dangerous path within the span of a five-year term.

There would be international pressure too. Global and bilateral nonproliferation instruments such as the Treaty on the Non-Proliferation of Nuclear Weapons, the Comprehensive Nuclear-Test-Ban Treaty, the 1992 Joint Declaration of the Denuclearization of the Korean Peninsula, and the 2015 US–Republic of Korea Nuclear Cooperation Agreement strictly prevent the Seoul government from going nuclear. In short, South Korea is restrained not only by a powerful nuclear taboo but also by the International Atomic Energy Agency’s water-tight monitoring presence.

Even if acquiring them is infeasible for now, support for nuclear weapons is more and more in fashion. South Korean policy elites understand that the country is fundamentally responsible for ensuring its own security in an anarchic world. If the United States and the world want to prevent South Korea from starting a nuclear weapons program, it is essential that Washington work toward a nuclear freeze in North Korea and reaffirm its commitment to the bilateral alliance.