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North Korean Nuclear Test: What Is the Nature of the Threat?


South Koreans watch state coverage of North Korea's third nuclear test. Photo: Getty

South Koreans watch state coverage of North Korea’s third nuclear test. Photo: Getty

From a global perspective, any new entry into the “nuclear club” is high undesirable as such: With every new entrant, there is an exponential increase in the political complexity of achieving total nuclear disarmament — or, to put it more simply, there is an additional obstacle in the way of eliminating all weapons of mass destruction.

But with every new entrant there also are immediate security concerns, and those concerns understandably hog most of the immediate attention. In the United States, the major preoccupation is whether a North Korea equipped with intercontinental ballistic missiles that are outfitted with nuclear weapons could threaten the United States. Fortunately, that is a completely implausible threat. Under no conceivable circumstances would the North Koreans lob a few second-rate nuclear weapons in the direction of the United States, knowing without a shadow of a doubt that doing so would lead to the immediate and complete destruction of their current regime. Obviously the United States would not turn its other cheek is such a situation, and obviously its retaliation would be a hundred times more devastating than the North’s pinprick.

(The vanishingly small probability of such an attack is especially fortunate because, to judge from the lead article in the current issue of Arms Control Today, the United States has just wasted $250 billion on the construction of a strategic missile defense system to guard against just such a threat that is scientifically ungrounded and, so far, almost completely unsuccessful.)

To say there is no strategic threat to the United States from a growing North Korean nuclear capability does not mean, however, that there is no threat at all. The real threat, in a nutshell, is that the ever-insular and ever-paranoid North Korean leadership might use a small but deadly nuclear deterrent as cover for an all-out conventional attack on South Korea. If the South (with or without its ally the United States) sought to counter with an attack on the North — a strong offense being the best defense–the North could threaten the South with annihilation of its largest cities, without directly involving the United States. It is a scenario fit to conjure for South Koreans the quandary of whether the United States would be willing to sacrifice Chicago for Seoul — a quandary exactly analogous to that the Germans worried about at the height of the Cold War.

If this kind of scenario seems far-fetched, consider the fundamentals: Since 1990, when the East German regime abruptly imploded and the two Germanies were suddenly re-united entirely on the Federal Republic’s  terms, it can safely be assumed that North Korean leaders lie awake nights wondering whether the same fate might befall them. Eventually the two Koreas are bound to be united, and inevitably reunification will be either on the South’s or the North’s terms.

Immediately after the North Korean nuclear test earlier this week, Siegfried Hecker, a former director of Los Alamos National Laboratory, told the New York Times that he expected one immediate effect would be to spur work on regional missile defenses in South Korea and neighboring countries. It was Hecker to whom the North Koreans unexpectedly revealed several years ago the existence of their uranium enrichment program. “Threatening a missile-capable warhead with a successful third nuclear test gives the United States, South Korea and Japan good reason to step up their regional ballistic missile defense capabilities,” said Hecker, who is now at Stanford and has been a frequent visitor to North Korea in recent years.

Hecker’s prediction seems sound, and not just because Hecker is Hecker. Though the United States as such faces no credible nuclear threat from North Korea, South Korea certainly faces such a threat, and perhaps its non-nuclear neighbors do as well.

Could regional missile defenses actually mitigate the threat facing the South, given the failure of the United States to develop credible strategic defenses, even after decades of effort and the expenditure of hundreds of billions of dollars? It seems they might. Although this may seem slightly counter-intuitive, experts seem to generally agree that effective strategic defense systems are a lot harder to conceive and develop than regional (or non-strategic) systems.

Even though shorter-range offensive missiles obviously reach their targets faster, giving defenders less time to react, other, weightier considerations favor regional defense technologies. The two major reasons are that intercontinental ballistic missiles, traveling at speeds as high as 15,000-17,000 miles per hour,  approach their targets enormously faster than their shorter-range counterparts would;  and, while in the frictionless environment of outer space, vehicles carrying nuclear weapons are very hard to distinguish from easy-to-make decoys, shorter-range warheads tend to separate from decoys traveling in the atmosphere.

Phil Coyle, the author of the devastating article about strategic missile defenses in the current issue of Arms Control Today, vividly expresses the second point as follows: “The drag from traveling through the atmosphere can strip off [any] decoys, countermeasures, or debris from [rocket]  stage separation [that are] traveling with the reentry vehicle.  In the vacuum of space, a balloon can travel as fast as a lead brick.”

What is more, Coyle continues, “to reach longer range systems, the interceptor has to travel much faster and farther to even get close.  If I throw a rock directly at you, you might be able to bat it away.  But if I throw that rock into the farthest corner of the room, and your job is to defend that corner, you’ve got to be really fast to get there before the rock lands.  And if your job is to defend not just that room but every corner of a town, a city, or a country before that rock lands, you’ve got to be really fast, like Superman, to get there before the rocks lands.”

To say that regional missile defenses are more plausible than strategic defenses is not to say, of course, that efforts to develop them will be successful or that the end product will be good enough. By general expert consensus, defenses against non-nuclear short- and medium-range missiles are more likely to be useful and effective than defenses against nuclear-tipped missiles; to be really convincing, a regional system, like strategic systems, would have to find and kill all incoming nuclear weapons, without exception. With conventionally armed missiles, it’s worth having even a relatively simple system like Israel’s Iron Dome that knocks out, say, 80 or 90 percent of the missiles that represent real threats.

But even taking that critical consideration into account, it seems safe to say that the technically adept South Koreans will be doing everything they can to develop non-strategic missile defenses. Whether or not one approves that course of action or expects it to be successful, the threat is sufficiently real to make the effort all but a foregone conclusion. Last October, South Korean defense authorities let it be known that they would not participate in development of a multi-layer U.S. regional missile defense system but instead stay focused on single low-altitude interceptors.

“Alongside PAC-2, Hawk, and SM-2/6 interceptors, three new types of interceptors will form Korea’s missile defense.” said an online news report on Oct. 26, 2012. “On the lowest tier, it will be K-SAAM, a small dual-seeker interceptor developed by LIG Nex1 with strapdown IR and microwave radar. On the medium tier, it will be a modified hit-to-kill variant of Iron Hawk/Sky Bow-II KM-SAM (which currently uses directional warhead for anti-aircraft). On the highest tier, it will be a new exoatmospheric interceptor codenamed L-SAM, with engagement ceiling of 60km to more than 100km altitude, that will be developed in a $700 million project starting this year. A new TBM multifunction radar will also be developed having dual S/X-band multi-beam AESA features.”



William Sweet

Bill Sweet has been writing about nuclear arms control and peace politics since interning at the IAEA in Vienna during summer 1974, right after India's test of a "peaceful nuclear device." As an editor and writer for Congressional Quarterly, Physics Today and IEEE Spectrum magazine he wrote about the freeze and European peace movements, space weaponry and Star Wars, Iraq, North Korea and Iran. His work has appeared in magazines like the Bulletin of Atomic Scientists and The New Republic, as well as in The New York Times, the LA Times, Newsday and the Baltimore Sun. The author of two books--The Nuclear Age: Energy, Proliferation and the Arms Race, and Kicking the Carbon Habit: The Case for Renewable and Nuclear Energy--he recently published "Situating Putin," a group of essays about contemporary Russia, as an e-book. He teaches European history as an adjunct at CUNY's Borough of Manhattan Community College.