Thunder Run to Seoul: Assessing North Korea's War Plan

For Westerners, North Korea is perennially on and off of the headlines. This year, the confluence of a new US president, the US missile attack in response to the use of chemical weapons in Syria, and an apparently in-your-face program of missile and nuclear tests on the part of North Korea has returned the world’s last Stalinist state to comment threads and coffee-room speculation. Military professionals obviously follow these events even more closely, and Maj. ML Cavanaugh’s recent thoughtful pieces for MWI serve as an example.

The China Wildcard

The first and biggest assumption is that China would not intervene. It is of course possible that renewed fighting on the Korean peninsula could arise as a consequence of Sino-US conflict elsewhere. On one hand, this scenario is actually better for the defending ROK/US forces since the outbreak of Sino-US conflict elsewhere would presumably trigger heightened readiness in South Korea and this would eliminate one of the main pillars of North Korea’s war strategy—operational surprise. On the other hand, even limited war elsewhere in Asia would reduce the numbers of US forces available to fight in Korea and threaten ROK/US plans to establish air supremacy over the peninsula.

Regardless of how war breaks out, a Korean campaign would still most likely begin the same way: with an attack by in-place North Korean forces which will likely be defeated. Once that initial attack is absorbed and ROK forces have been fully mobilized, ROK/US forces will be in a position to go over to the offensive, advance into North Korea, and decisively defeat DPRK forces. The main factor that will determine the later outcome is the potential presence of Chinese forces: If China stays out, expect a fairly quick defeat of North Korean forces, and presumably the regime. But Chinese intervention would probably result in the war becoming stalemated just as the first conflict did. The terrain in Korea favors defense and limits the forces which can be employed, so that with Chinese forces committed, neither side could be expected to achieve a decisive advantage.

It is also possible to imagine scenarios in which China signals a willingness to intervene—or actually intervenes—to prevent the complete collapse of a DPRK that has been defeated on the battlefield. These kinds of what-happens-once-we-defeat-Kim problems are difficult and professionally fascinating, but this article is concerned with how we get there and so will assume that, whatever diplomatic end-game is developing off-stage, China has not intervened in any significant way.

The North’s Attack Plan

So what would the initial North Korean attack look like? Unlike in 1950, when Soviet, Chinese and North Korean planners had a realistic prospect of conquering South Korea in a war, an attack today has only a small chance of victory within a narrow time window. In 1950, DPRK forces enjoyed large initial advantages in numbers, troop quality, and all classes of equipment including tanks and aircraft. Today all of those initial advantages except artillery and numbers are on our side, and even the numbers are more balanced. DPRK planners recognize their inferiority in technology and, after ROK mobilization, even in numbers. They understand that ROK/US forces will have air superiority initially, and (unless China intervenes) air supremacy within days. They therefore plan to win by striking quickly, by surprise, while ROK forces are still mobilizing, US reinforcements are not yet in theatre, and while our airpower is largely committed to overcoming the DPRK integrated air defense system and targeting WMD storage sites, launchers, and command, control, and communications (C3) networks.

Recognizing that ROK forces will be on some degree of heightened readiness during a crisis, the regime will use its formidable intelligence and special operations capability to obscure preparations for an attack and slow ROK responses. Its own past history of symbolic attacks, placing its forces on alert, and angry promises to destroy its enemies will actually work in its favor in this case: ROK/US intelligence agencies will expect some kind of posturing from the North and may therefore misidentify attack preparations as lesser actions. DPRK agents will also count on the psychological reluctance of the South Korean population and government to believe that war is imminent. They will actively seek to influence the ROK democratic decision-making process to get inside our decision cycle. In particular, ROK mobilization will require a political decision and every hour of delay imposed through threats, deception, information and cyber attacks, or direct action will have consequences. In the end, even if ROK/US commanders do recognize the signs of an attack before it begins, it will still take time to react. In that time, DPRK commanders hope to win.

There will be no need for detailed orders. Just as ROK forces know and rehearse their war plan, DPRK forces are largely in place, in numbers sufficient to achieve some local breakthroughs on the major routes towards Seoul—their first operational objective. North Korea will hope to begin mobilization before South Korea does, and thereby turn their currently modest advantage in numbers into a temporarily significant one. DPRK forces will rely, Soviet-style, on the use of overwhelming artillery and rocket fires to break through ROK prepared positions along the DMZ, while using deep fires to attack C3 nodes, routes forward, and mobilization centers. Strikes against targets in Seoul and the surrounding urban areas will have the additional useful effect of causing fear and choking routes with a panicked populace.

On the subject of routes it is worth considering the limited space for mechanized maneuver in central Korea: The eastern half of the peninsula is largely mountainous with roads running along valley floors. The grain of the country will tend to push DPRK forces southwest (towards Seoul). The western half of the peninsula around Seoul and the Han River system is slightly flatter, but at least south of the DMZ the land is now so built up that once major routes come under fire it will be slow going for both sides. It’s not good country for heavy forces, and until recently both sides planned to use mostly lighter infantry to fight on the line. Recent announced changes to ROK force structure see a much greater emphasis on heavy forces—perhaps to get more combat power out of a smaller overall force—but the terrain suggests that such forces will likely be difficult to maneuver. Furthermore, DPRK tactics emphasize the use of infiltration to achieve local penetrations and attack deeper, tactical targets. Their line formations include elite sub-elements specially trained for these tasks, and the terrain—whether urban or forested mountain—is ideal for it. Road-bound heavy forces will be especially susceptible to such tactics.

The final element in the DPRK plan is an extensive deep battle across the entire South Korean depth using some one hundred thousand special operations forces (SOF). An interesting feature of this war is that since both sides look and speak more or less alike, covert insertion and operation is easier for each side—but especially so for North Korean agents who may move freely within South Korea’s open society.

Some DPRK SOF will have been pre-positioned. More will be inserted by sea, air, and ground infiltration shortly before the main attack, exploiting—little-green-men-style—any public uncertainty or national command paralysis for temporary deniability. One of the main tasks for DPRK SOF in this preliminary phase will be to support the deception plan by encouraging and magnifying whatever confusion and chaos may accompany a crisis, and especially to foster political uncertainty and indecision in the critical hours before the main attack. Deniable attacks against political leadership, false-flag provocations, staged anti-war protests, terrorist attacks aimed at causing panic, and limited attacks against key C3 nodes will begin in this stage. This phase could last for days or even weeks, but hours are more likely.

Once DPRK main forces attack across the DMZ, the remaining DPRK SOF will surge south by sea and air towards targets in Seoul and in depth. Many will be destroyed en route by defending ROK forces, and more will be defeated at their objectives, but DPRK planners hope to overwhelm ROK defenses by sheer numbers of SOF and inflict temporary but serious damage while they still have operational surprise. SOF targets in this phase will be national C3 nodes, including political leadership, mobilization centres, airfields, ports and naval bases, and choke points on major routes. As with artillery strikes, fighting by SOF on objectives in Seoul will be aimed at heightening panic and demoralizing political leadership, and will be exploited by DPRK information warfare agencies to give the impression that the front has already reached the ROK capital.

With luck, DPRK planners hope to have main forces entering Seoul within the first week, from which position they can either transition to defense and negotiate from strength or, if conditions permit, push on to decisively defeat ROK forces.

But this plan is very optimistic. ROK planners understand it well and are prepared to counter it. Forces defending along the DMZ are in strong, prepared positions supported by obstacles. ROK C3 is hardened and redundant. Rear-area security forces are substantial and their plans are kept current and rehearsed. Even given some disruption by DPRK SOF, mobilization is expected to generate millions of men within days.

The Unknowns

There are three main variables which might affect this estimate: First, the combat performance of either side cannot be known for certain. My own guess is that ROK forces would fight very well—especially on defense. But there are ways in which North Korea may attempt to undermine ROK morale: Both sides consider the other to be cousins awaiting liberation and this could be used as part of a skillful information operations campaign—particularly if ROK forces seek to advance into the North. The possible combat performance of DPRK forces is even less predictable. On the one hand, the DPRK population has been brainwashed from birth. On the other hand, North Korea’s people fear their own leadership and are often on the brink of starvation. It is possible that they might fight fanatically, but also that, given a chance, they would turn on their leaders. We simply don’t know.

The second main variable is the potential DPRK use of WMD. Finding and killing these will be a high priority for ROK/US commanders, but it is possible that some will survive, especially in the first few days. The North’s leaders may decide to use chemical weapons for battlefield advantage or, if they fail to enter Seoul, may seek to blackmail the ROK government with the possibility of chemical or even nuclear attack against it. Of course the use, or even threatened use, of WMD might invite US retaliation in kind, but a desperate or simply risk-taking Kim regime could gamble that our side would blink first.

The third and related variable is what the DPRK regime would do in defeat. Facing defeat, it is possible that army commanders, or even their troops, would turn on the leadership and depose the regime. On the other hand, if Kim retains enough control over his forces but believes that he is on the brink of being deposed, it is possible that he could—with nothing left to lose—simply unleash whatever WMD he still possesses.

The Takeaway: DPRK Will Make it Ugly

Recognizing that in war nothing ever goes entirely as expected, and that there are some major unknowns, this is based on what we do know about North Korea’s force structure, its comparative strengths, and terrain and other considerations—along with my own assessment of how Korean War II would initially unfold. But regardless of how it played out, one thing is near certain: It would entail horrific destruction and suffering. Tens or hundreds of thousands could become casualties. In defeat, North Korea would become a 25-million strong humanitarian catastrophe. And that is just with conventional weapons: The possible consequences of attacking Seoul with WMD are almost too awful to contemplate. There is a role for force here—a strong ROK/US posture has certainly constrained North Korean aggression for decades—and in no way should DPRK threats be simply acceded to. But under current conditions, and given the scale of likely destruction, planners should strongly question whether each DPRK provocation—even the imminent development of a ICBM—justifies risking such a war.

Lt. Col. Raymond Farrell is an officer in the Canadian Army. He is a graduate of ROK Army Command and Staff College and studied at the US Joint Targeting School.

The views expressed here are those of the author and do not reflect the official position of any agency of the Canadian government.

This article appeared originally at Modern War Institute.