When U.S. President Donald Trump and South Korean President Moon Jae-in meet this week, they are certain to discuss Seoul’s plans to build larger, nuclear-capable ballistic missiles. The White House has already signaled its willingness to back this effort, and talks about how to do so are underway. These talks were planned despite recent reports of warming ties between Beijing and Seoul. But if the United States is serious about reducing the prospects for war and nuclear missile proliferation, as well as strengthening its alliance with South Korea, the Trump administration cannot hand South Korea a blank check. At the very least, it should put limits on the range of Seoul’s missiles and ensure that the United States retains a say in when they are used.

This would be in line with over 40 years of the alliance’s history. U.S. efforts to limit South Korea’s missile ambitions date back to when Seoul was first caught trying to acquire nuclear weapons, in the 1970s. In exchange for access to basic American missile technology, South Korea agreed not to build any ballistic missiles that could travel more than 110 miles. To help ensure that Seoul did not violate this agreement, the United States conducted inspections of South Korean missile facilities.


As the North Korean threat has grown in recent years, Seoul has repeatedly strengthened its missile forces. First, in 2001, South Korea got the United States to agree to extend its missile range limit to 185 miles while carrying a 1,100-pound warhead. Then, in 2012, the two countries reached an agreement that permitted Seoul to build ballistic missiles able to travel 500 miles—enough to cover all of North Korea—while carrying a 1,100-pound warhead. The same agreement also allowed South Korea to build missiles with larger payloads but shorter ranges. Under these later agreements, it is unclear whether the United States continued to conduct formal inspections.

Now, Seoul wants to place a 2,200-pound warhead on its longest-range missile. The Trump administration appears ready to agree; the president said he agrees in principle and Secretary of Defense James Mattis recently confirmed that the two sides are negotiating specifics.

The problem is that the missile issue is not taking place in a vacuum. Seoul is trying to build these nuclear-capable missiles at a time when an increasing number of South Korean lawmakers are advocating nuclear weapons. Even without nuclear warheads, South Korea wants more powerful ballistic missiles with which to implement its so-called Kill Chain doctrine. Under this controversial strategy, Seoul is acquiring the capabilities to conduct preemptive military strikes on North Korea’s nuclear and missile sites and target Kim Jong-Un and his deputies, independently of the United States.

The United States needs to insist that it be included in any decision to launch preemptive strikes on North Korea.

As a sovereign nation, South Korea has a right to defend itself. At the same time, the United States has over 28,000 troops in South Korea. All of them would become prime targets following any preemptive attack by South Korea. Seoul demands that no U.S. first strike be made against North Korea without its prior consent, and the U.S. should insist on no less for itself. It is not just the lives of tens of thousands of American soldiers overseas that are at stake, but millions of civilians back home.

Some may contend that the United States already has a say, because current plans call for South Korean forces to be put under U.S. command during times of war. This ignores the fact that the South Korean president alone determines when the country has entered into a war, and Seoul appears to believe that preemptive strikes take place during peacetime, when South Korean troops are under the command of their own generals. In 2013, General Jeong Seung-jo, the then-chairman of the South Korean Joint Chiefs of Staff, said “a preemptive attack against the North trying to use nuclear weapons does not require consultation with the United States and it is the right of self-defense.” The issue may soon become moot, since South Korea is pushing the United States to relinquish wartime control over its forces. In turn, the United States risks being cut out of the chain of command that makes decisions about launching preemptive attacks, despite its troops still being in the line of fire.

South Korean and U.S. Marines training in Pohang, South Korea, March 2016.
South Korean and U.S. Marines training in Pohang, South Korea, March 2016.
Kim Hong-Ji / REUTERS

Fortunately, this outcome is preventable. In exchange for allowing South Korea to build its heavier ballistic missiles, the Trump administration should ask that the range of its missiles not extend beyond 500 miles, so as to limit the threat to China and Japan. In addition, South Korea should agree not to use these missiles to deliver nuclear weapons. To enforce both conditions, South Korea should allow American inspections. Finally, the United States needs to insist that it be included in any decision to launch preemptive strikes on North Korea.

An agreement that allows South Korea to build new ballistic missiles in exchange for these conditions would not just strengthen its defenses, but would  put the U.S.–South Korean alliance on stronger footing at a time when North Korea is testing its durability.

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  • ZACHARY KECK is the Wohlstetter Public Affairs Fellow at the Nonproliferation Policy Education Center. HENRY SOKOLSKI is Executive Director of the Nonproliferation Policy Education Center.

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