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North Korea’s intense series of ballistic missile tests since last year has brought Kim Jong-un ever closer to mastering the capability to hit the continental United States. Washington and its allies are now acutely confronting the problem of how best to deter North Korea militarily, even as U.S. and regional policymakers continue to look for a way to convince Kim to stand down and reverse direction.
North Korea’s ballistic missile development has persisted for decades. As listed by the Center for Strategic and International Studies’ Missile Defense Project, existing and developing capabilities include:
- Short-range ballistic missiles or SRBMs, with ranges defined to be 1,000 kilometers or under (KN-02, Hwasong-5 and 6, KN-18, and Scud-ER/extended-range Hwasong-6)
- Medium-range ballistic missiles or MRBMs, with ranges defined to be between 1,000 and 3,000 kilometers (No-dong, KN-11, and KN-15/Pukguksong-2, all under the range of 2,000 kilometers)
- Intermediate-range ballistic missiles or IRBMs, with ranges defined to be between 3,000 and 5,500 kilometers (Musudan and Hwasong-12)
- Intercontinental ballistic missiles or ICBMs, with ranges defined as at least 5,500 kilometers (KN-08, KN-14, Hwasong-14, and Taepodong-2, all of which have ranges of at least 10,000 kilometers)
- The North Korean arsenal also includes cruise missiles, surface-to-air missiles, rocket launchers, and various artillery pieces
The diverseness of North Korea’s missile arsenal suggests that the Kim regime desires to practice deterrence vis-à-vis the United States both through denial of U.S. attack options and punishment for any attack.
To begin with, Seoul, located thirty miles from the demilitarized zone, has always been hostage to North Korean conventional military threats, and now North Korea seeks to make Japanese and U.S. cities hostage to the threat of nuclear-tipped ballistic missiles. The North Koreans are seeking to establish deterrence by threatening to punish their adversaries with unbearable human cost if attacked.
The North Koreans have also been developing the capability to strike U.S. bases in South Korea, Japan, and Guam with nuclear weapons, thereby seeking to minimize the chance of a U.S.-led attack succeeding by holding U.S. troops and transit/supply lines to the Korean front at risk and by seeking to greatly raise the cost of such an attack. The North Koreans are seeking to establish deterrence by seeking to deny the adversaries’ capability to achieve their objective.
But the purpose of North Korea’s growing arsenal seems to go beyond deterrence. The North Koreans continue to call on the United States to sign a peace treaty that would likely include the withdrawal of U.S. troops from the Korean Peninsula and the end of the U.S.-South Korea alliance. Many experts suspect that Kim, after pushing the United States out of the Korean Peninsula, would seek to unify Korea on his terms by using or threatening to use nuclear weapons. With the North’s testing of ICBMs, there are growing concerns that the credibility of U.S. extended deterrence to South Korea would weaken if a major U.S. city (Los Angeles, for example) were to come under the threat of a nuclear strike. Many fear that the perception of American irresolution could tempt Pyongyang to seek Korean unification by force.
In response, the United States and its allies have been redoubling efforts to deter and defend against North Korea’s expanding missile threat.
The American strategy for deterrence by punishment, at least since the end of the Cold War, presumes that a major North Korean attack would result in the end of the Kim regime. For example, President Donald Trump has stated in his UN speech, albeit in an overdramatic manner, that, if “forced to defend itself or its allies,” the United States would have “no choice but to totally destroy North Korea.” The South Koreans have also stated that they will go after the North Korean leadership and have even announced the formation of a unit specifically created to decapitate the North Korean leadership.
With regard to deterrence by denial, the United States has been developing and deploying multiple types of missile defense systems. The Ground-based Midcourse Defense (GMD) system's interceptors are deployed in Alaska and California to defend against intercontinental ballistic missiles. Aegis SM-3 missiles are deployed on ships in the Pacific to defend U.S. and allied targets in the region. The Terminal High Altitude Area Defense (THAAD) system is deployed in South Korea and Guam for area defense, while the United States has also deployed Patriot batteries for point defense throughout the region. Japan and South Korea also have their own missile defense capabilities, although rather limited compared to U.S. capability.
To strike and destroy North Korea’s nuclear weapons capabilities, the United States has B-2 bombers and F-22 fighter aircraft in the region that can be used to penetrate North Korean airspace to hit nuclear and missile targets. In addition, the U.S. navy can launch cruise missiles. The South Koreans, as part of their preemptive doctrine, are deploying ballistic and cruise missiles to strike North Korea’s nuclear and missile capabilities. Missile defense systems are expected to intercept any missile that initial strikes had failed to destroy. Without clear intelligence on North Korean targets, the likelihood of success of such strikes would be uncertain, however, and North Korea’s capability to massively retaliate against South Korea gives pause to any preventive option.
As the North Koreans continue to develop their missile technology and increase the size of their arsenal, they will likely gain the advantage in terms of cost-benefit calculations vis-à-vis the United States. Assuming that North Korea will have dozens (or perhaps even far more) nuclear-tipped missiles, the United States and allies would have the task of destroying or intercepting every single one of them, while North Korea only needs one warhead to land on a densely populated area to potentially kill hundreds of thousands of people. It does not help that GMD only has the accuracy rate of approximately 50 percent under relatively benign circumstances and that the current "shot doctrine" states that the United State will be firing four to five interceptor missiles for every incoming ICBM. Taking into account the possibility that the North Koreans might develop dummy warheads, the task of defending against the North Korean threat will likely become more difficult into the future. These factors increase the American sense of urgency and raise the risks of preemption higher as North Korea edges closer to mastering the capability to directly threaten the continental United States.
As the North Koreans advance their nuclear weapons capability, creating a more stable deterrence dynamics on the Korean Peninsula will become more complex. But just as the North Koreans merely have to create the possibility that a single warhead might slip and land on an American city, the Americans merely have to create the possibility that North Korean plans to decouple the U.S.-South Korea alliance and seek unification on Pyongyang’s terms might not work out. While the United States faces the cost-benefit disadvantage that naturally derives from deploying any missile defense system, its economy is also immeasurably larger than that of North Korea, which will have its own limit in increasing the size of its arsenal.
The United States should continue to seek a diplomatic pathway to denuclearize North Korea. But regardless of prospects for a diplomatic settlement, the United States and its allies still have the means to create stable deterrence on the Korean Peninsula and should deepen their security cooperation to do so.