Can South Korea Trust Trump?

In Seoul, the U.S. president urged North Koreans to negotiate. The South should hope he’s serious.

Donald Trump shakes hands with South Korean President Moon Jae-in.
Donald Trump shakes hands with South Korean President Moon Jae-in during a dinner in the White House, Washington, on June 29, 2017.  (Carlos Barria / Reuters)

As President Trump was kicking off the first state visit under the progressive administration of Moon Jae In, the life-or-death question in South Korean minds was whether Trump intended to take an America-first or an alliance-first approach in response to the growing North Korean threat.

How Trump views American alliance commitments to defend South Korea from North Korean aggression has become an urgent question as North Korea has expanded the range of its missiles and the yield of its nuclear explosions.  When the North Korean foreign minister threatened an above ground thermonuclear test in response to President Trump’s threat at the United Nations in September to destroy the country, there was every reason for South Koreans to worry that the war of words might trigger a military conflict, with potentially catastrophic consequences for South Korea. They may have been reassured somewhat when Trump, at a joint press conference with Moon in Seoul, urged the North Koreans to “come to the table and make a deal,” stating that military options are a last resort and that the current strategy remains one of economic pressure and political isolation.

Yet despite what Trump called “movement” on the issue, denuclearization remains a distant goal—and Trump’s ultimate strategy an open question. North Korean leaders believe that the ability to strike the United States with nuclear weapons will finally even the nuclear playing field, after it has lived under what it sees as the threat of American nuclear attacks for decades. Trump has stated that the United States will not tolerate vulnerability to a North Korean nuclear strike capability—which is getting ever-closer as the North approaches the means to fit a nuclear warhead on an intercontinental ballistic missile—and that “Rocket Man” is on a suicide mission. But the South Korean capital city of Seoul is only a few dozen miles south of the Demilitarized Zone (DMZ) and has lived with the risk of destruction from North Korean artillery and rocket launchers for decades, making redundant the threat from North Korea’s nuclear weapons that Koreans have lived with following North Korea’s first nuclear test in 2006.

Kim Jong Un has stated that an “equilibrium” with the United States will remove the risk of an American attack on Pyongyang, despite worrisome evidence to the contrary. Both statements reveal misplaced assumptions that raise the risk of miscalculation and pose new tests for a U.S.-South Korean security alliance that has helped deter renewal of war with North Korea for decades.

South Korea’s embrace of the security alliance with the United States has proven to be the country’s best strategy for securing its stability and prosperity, even at the cost of South Korean aspirations for autonomy. The clash between the need for an alliance protector and the desire for autonomy has evolved as a result of South Korea’s democratic transformation and as South Korea has become the dominant power on the peninsula, surpassing the North in the 1970s.  South Korea’s dependency on the United States has remained critical in facing down North Korea’s nuclear threat, as well as managing China’s rise—not least because South Korea’s embrace of global trade interdependence relies on rules made by the United States.

But South Korean domestic debates about America’s reliability have grown in recent years on issues such as how to balance relations between Beijing and Washington. More recently, South Korean debates have centered on whether to request a return of U.S. tactical nuclear weapons to South Korean soil, or even whether South Korea should develop its own nuclear weapons to balance the North. Just last week, the Moon administration started walking the high wire in Moon’s diplomacy with Trump and Xi Jinping as it launched what it calls “balanced diplomacy,” the goal of which is to pursue a diplomatic rapprochement with China following over a year of friction over the U.S. deployment of the Terminal High Altitude Air Defense (THAAD) missile-defense system in South Korea. While emphasizing the importance of joint U.S.-South Korean defense and deterrence against North Korea, Moon reiterated the importance of balanced diplomacy as a way of diversifying South Korea’s diplomatic relations at his joint press conference with President Trump. But this effort has generated debate about whether Moon is sacrificing potential for strengthened trilateral U.S.-Japan-South Korean security cooperation for the sake of better relations with Beijing.

Still, given the effectiveness of the U.S.-South Korean security alliance in deterring conventional aggression from a far weaker North Korean adversary, Pyongyang, using its classic guerrilla mindset and tactics, has been testing the alliance with unconventional challenges. One end of the spectrum involves unconventional provocations short of war, as when the North Korean sinking of a Korean naval vessel and shelling of a South Korean-controlled island near the North Korean mainland in 2010 raised the risk of South Korean unilateral retaliation. In those cases, U.S. Forces in Korea counseled restraint.

On the opposite end of the spectrum, of course, is the nuclear threat on the U.S. mainland, which has reversed this dynamic, with South Korean president Moon insisting in a speech to the National Assembly days prior to President Trump’s arrival in Seoul that “no military action on the Korean peninsula will be taken without the prior consent of the Republic of Korea.” In both instances, a primary source of tension is whether an America-first approach involving unilateral U.S. action, or an alliance-based approach, is likely to be a more effective solution to the problem.

The America-first approach to North Korea runs the risk of playing into Kim Jong Un’s hands. North Korea’s quest for the capability to strike the United States allows it to test the credibility of American security commitments—would the U.S. president really risk Los Angeles to save Seoul if North Korea invaded the South?—demand withdrawal of U.S. forces from South Korea, and pursue North Korean-led unification of the Korean peninsula. On the one hand, South Koreans worry about the risk of American abandonment of South Korea under threat of North Korean blackmail. On the other hand, they worry that a premature American strike on North Korea will entrap South Korea in a conflict that could potentially cost millions of Korean lives and threaten the economic base of one of the top 15 economies in the world. North Korea’s pressure on the alliance, combined with America’s own mixed signals—for instance Trump’s suggestion that South Korea and Japan should pursue their own nuclear arms during the election campaign—may together give Kim Jong Un hope that Trump might cave in and bring U.S. Forces in Korea home.

From an America first perspective, the Trump administration will want to examine every measure available to prevent North Korea from expanding its power to extort respect and resources from the rest of the world. In this view, the idea of nuclear vulnerability to Kim Jong Un is intolerable and must be stopped at all costs, including preventive war. But a premature unilateral strike on North Korea will most probably break both the U.S.-South Korea alliance, by precipitating a South Korean domestic backlash over whether conflict was necessary, and endanger the U.S.-led security architecture in Asia—in addition to forcing the United States to bear disproportionate costs for a protracted post-conflict stabilization process on the Korean peninsula.

On the other hand, an alliance-first approach to countering North Korea supports the continuation of the Trump administration’s maximum pressure and engagement campaign against North Korea. It holds the line on North Korean dreams of coercing the South into Korean unification while countering North Korean threats with certain knowledge in Pyongyang that crisis escalation would prevent Kim Jong Un from achieving his essential objective of regime survival, a solid form of restraint against North Korean adventurism. It should buy the time necessary to fully implement the Trump administration’s efforts to squeeze North Korea by building ever-greater coercive pressure in support of a diplomatic solution to the current crisis. Significantly, the strategy uses economic coercion in a fashion that more fairly distributes costs to all the concerned parties, including China, by forcing China to accept the necessity of sanctions enforcement.

Most importantly, the U.S.-South Korea alliance serves as an important brake on premature military action through preventive war without compromising U.S. capability to take actions in its own self-defense—actions which ultimately would be understandable to American allies—in the event that North Korea were to launch an attack on the United States.