Aegis is Key to Deterring North Korea
During February and March, Kim Jong-Un continued to escalate his war of nerves against South Korea and its ally, the United States. The North Koreans appeared to be preparing for another nuclear test, and Kim Jong-Un keeps claiming he will soon unveil an unprecedented rocket development, which is likely to be an intercontinental ballistic missile (ICBM). Ultimately—it is not clear how soon—such a missile would enable North Korea to threaten the United States. Meanwhile in the United States considerable publicity was given to possible measures that could be used “to the left of launch” (i.e., prior to launch on a time line) to counter a North Korean attack. Such measures could include a preemptive strike (explicitly not eliminated as a possibility by Secretary of State Rex Tillerson) and cyber attacks, which, according to recent stories in the New York Times, had crippled earlier North Korean missile tests. Some U.S. experts warned that even an inaccurate North Korean ICBM could explode high over the United States to create an electromagnetic pulse (EMP) that could cripple a large area of the country and impose horrific damage. Much of the U.S. government’s discussion of “left of launch” measures was justified by reports that ground-based missile interceptors in Alaska and in California have proven unreliable in tests.
Remarkably, the discussion of possible defense against a North Korean attack seems to have omitted altogether a more successful U.S. ballistic missile defense (BMD) system—the Navy’s Aegis system on board destroyers in the Pacific. Unlike the fixed interceptors in Alaska and California, U.S. warships can be deployed close to North Korea to have a chance of engaging a missile in its boost phase and close enough to South Korea and Japan to be able to prevent an incoming missile from hitting our allies. Moreover, the deployment of Aegis ships is a U.S. decision, not dependent on foreign permission, and less visible publicly than ground-based systems. (Chinese and North Korean agitation about the deployment of the U.S. Army’s Terminal High Altitude Area Defense system (THAAD) in South Korea demonstrates some of the diplomatic challenges to ground-based systems.) Aegis BMD usually is described as a counter to regional missile threats such as North Korean and Iranian medium-range ballistic missiles. Proposed Aegis upgrades would have an even greater capability against ICBMs, particularly when linked with off-board sensors and missile tracking systems.
Behind all the discussion is a terrible possibility. The usual form of deterrence—the threat of a U.S. nuclear counterattack—may not work with Kim Jong-Un. Like his two predecessors, he has shown little concern for the welfare of his people. It is doubtful he would care about their devastation, although Kim does care about his own welfare.
Preemption has received considerable publicity. Former President Barack Obama is said to have considered but rejected the idea. It is easy to see why. Any substantial attack by the United States on North Korea would be an act of war that others would probably see as justifying an attack by Kim. Conversely, Kim does not know how much we know, or what vulnerabilities we plan to exploit. It is possible that the threat of preemption is the most effective deterring threat we currently have. There is a precedent. Late in the Cold War, many American strategists concluded that the only real deterrent to a Soviet nuclear attack was a credible threat to destroy the Soviet leadership. To make this threat concrete, in a booklet describing the Soviet threat, the U.S. government published a simple map showing where the Soviet leadership planned to shelter in an emergency.
Ballistic missile defense is still controversial because it seems to be an alternative to stable deterrence. Critics have argued that a government with an effective ballistic missile defense system might feel emboldened to execute a first strike against a potential enemy, secure in the knowledge that the enemy could not strike back effectively. Given uncertainties in the performance of any mass defensive system, this argument seems ludicrous. Ballistic missile defense is insurance against an enemy attack, not encouragement for us to attack. In the current situation, the United States has deployed a defense to deal with the sort of small attack Kim might be able to launch; it might even be able to cope with the numbers of missiles China can currently launch. It certainly could not deal with the sort of mass attack the Russians could launch.
It seems unlikely that Kim is planning to attack the United States out of the blue. He is far more focused on a desire to reunite Korea by force. The last time the North Koreans tried to overrun the South, the United States was the main barrier to success; Kim may imagine that this is still the case—though South Koreans would disagree, having built up a strong military of their own. In building a nuclear arsenal, Kim may believe he is building a decisive deterrent against us.
Some years ago, Chinese leaders often asked Americans whether they would trade Los Angeles for Taipei—in other words, would the United States risk a nuclear strike against U.S. soil to protect Taiwan. Kim can ask a similar question: How much is Seoul worth to the United States? For many years, the United States has maintained peace in the western Pacific largely with its nuclear umbrella, a concept strategists call “extended deterrence.” Kim now is trying to put holes in that umbrella.
The question is how to convince Kim that his big investment in missiles and nuclear weapons has not bought him the deterrence he wants. Ballistic missile defense has to be a large part of imposing that uncertainty, and Aegis ships are integral to giving Kim pause, especially because they have been demonstrated numerous times to work reliably and because they can be deployed close to the Peninsula. Ground-based interceptors in North America—particularly if reports devalue them—contribute less to Kim’s worries.
Naval forces are also relevant to the threat of a North Korean EMP attack. The United States as a whole may be vulnerable to EMP, but U.S. strategic command-and-control has surely been hardened. Whether or not U.S. land-based strategic nuclear forces survived an attack, strategic submarines far from land would be outside any envelope of EMP damage. One Ohio-class ballistic missile submarine has enough firepower to destroy North Korea completely. Kim may or may not be able to live through a nuclear counterattack, but his regime would certainly be finished.
Ultimately deterrence works by uncertainty. No one can know exactly how well a nuclear attack would work, although there are plenty of methods to calculate projected damages. On the flip side, no one faced with attack can be certain that their defenses will work. Kim has to calculate his odds. The successful demonstrations of the Aegis ballistic missile defense system should give him pause. Ballistic missile defense increases Kim’s uncertainty and thus helps persuade him that his ballistic missiles are unlikely to work if he tries to attack South Korea, Japan, or the United States.
If Kim were to develop a credible threat to the United States and short-circuit U.S. deterrence, that could potentially ignite a war. We never want to have to ask ourselves whether defending South Korea might cost us Los Angeles or even more. The ability of U.S. naval forces to deter Kim from using nuclear weapons and long-range ballistic missiles is key to any attempt to calm the current situation. The South Korean and Japanese navies also brandish Aegis-equipped ships. Developing a trilateral BMD umbrella at sea might increase the overall deterrence effect on Kim. In this game of expectations, the demonstrated success of the Aegis ballistic missile defense system surely makes a considerable difference.
Dr. Friedman is the author of The Naval Institute’s Guide to World Naval Weapon Systems, Fifth Edition, and Network-centric Warfare: How Navies Learned to Fight Smarter Through Three World Wars, available from the Naval Institute Press at www.usni.org.