Pyongyang is upset over planned U.S.-South Korean exercises later this month, claiming that the war games are actually preparation for an invasion of the north.
Such statements are hardly unusual, and you can almost mark your calendar for the semi-annual propaganda blast from the Korean Central News Agency. Pyongyang usually makes these accusations before every joint military drill between American and South Korean military forces. The latest exercise starts Saturday, and will involve at least 20,000 U.S. and ROK troops. The Kitty Hawk carrier battle group arrived in Korean waters a few days ago, and will participate in the exercise, along with land-based air and ground units.
To show its displeasure, Pyongyang has vowed to "take the necessary countermeasures, including bolstering its nuclear arsenal to cope with this extremely hostile attempt by the U.S. to bring down the system" in North Korea. The North also recently pulled out of the six-party nuclear talks, and has also hinted that it could launch a preemptive attack to defend itself.
A preemptive strike by North Korea against its southern neighbor remains one of the greatest military and intelligence challenges facing the U.S. and its ROK allies. Pyongyang already has the military power in place to launch at least a limited attack across the DMZ, with little or no warning. According to some estimates, at least 60% of North Korea's army is located within 60 miles of the DMZ. That means that first and second echelon infantry, armored, SOF and artillery units are already in their pre-attack positions. Pyongyang has maintained this aggressive posture for years, and actually increased the number of long-range artillery positions along the DMZ during the 1990s.
With the bulk of the DPRK's ground forces near the DMZ, it becomes more difficult for intelligence agencies to assess North Korean readiness and intentions. In the intel business, it's called "unambiguous warning," and providing that kind of advance notice in Korea has become problematic (at best), despite constant surveillance by virtually every intelligence platform at our disposal. This problem is further compounded by North Korea's extensive denial and deception (D&D) program, which attempts to conceal sensitive military activity. Pyongyang is adept at using multi-spectral camouflage netting, an extensive network of underground facilities, and scheduling events outside intelligence collection windows, making it tougher for us to assess readiness levels, critical troop deployments, the redeployment of aircraft and other events that might precede a North Korean attack.
This is not to say that we lack good intelligence on North Korea. We still collect large amounts on information on the DPRK, but (as with any target) intelligence gaps exist, and those shortfalls can be exacerbated by North Korean deception efforts and high readiness levels during certain times of the year. In its diatribe against the U.S.-ROK exercise, the KCNA conveniently ignored the fact that Pyongyang is currently wrapping up its annual Winter Training Cycle, the three-month period when North Korean forces conduct most of their training. While overall training during the winter cycle decreased during the 1990s (due in part to fuel shortages), North Korea still conducts a tremendous amount of work at the battalion, regimental, division and corps levels, allowing all units the reach their readiness peak in late winter, when conditions for an invasion--most notably, off-road mobility--are at their best.
It would be difficult for NK to pull off another, full-scale surprise invasion of the South, as it did in 1950. Mounting a full-scale attack would require additional troop movements and preparations that we would likely detect. But detecting plans for a limited invasion would be more tricky, and that has clear consequences for the U.S. and South Korean militaries.
Why is the warning issue so important? Defense plans for South Korea are based on a rapid influx of U.S. reinforcements (notably airpower), and the full mobilization of the ROK ground reserve units--which actually outnumber their North Korean counterparts. Obviously, the more warning we have, the faster Washington and Seoul can react, by marshaling reinforcement and reserve forces. Without advance warning, the mobilization and reinforcement process would be delayed and lengthened, leaving allied forces at a numerical disadvantage in the early, critical hours of the war. Under that "worst-case" scenario, the National Command Authority might have to consider the use of nuclear weapons, to blunt a North Korean attack, particularly if DPRK SOF and missile attacks cripple air bases in South Korea.
Fortunately, a successful North Korean invasion of the south--limited or full-scale--is not a slam dunk. Pyongyang's forces have a number of shortfalls (including limited fuel supplies and vulnerabilities to PGMs) that could hinder their attack, slowing their rate of advance. And Kim Jong-il is well aware that once the U.S. arrives in force (and the ROKs complete their mobilization) his prospects for victory are about nil. So North Korea must strike hard, fast, and without tipping their hand in advance.
Despite the on-going nuclear crisis, the chances of the DPRK invading the south remain low. But the challenge of monitoring North Korea and divining its intentions remains difficult, and will probably grow more complex in the years to come, as Pyongyang improves its concealment skills and upgrades its communications network, and (of course) expands its nuclear arsenal.