OPLAN 5027 Major Theater War - West -- US-ROK Combined Forces Command basic warplan

Global Security, Inc.

August 30, 2003

OPLAN 5027 is the US-ROK Combined Forces Command basic warplan. Under Operations Plan 5027 (CINCUNC/CFC OPLAN 5027), the United States plans to provide units to reinforce the Republic of Korea in the event of external armed attack. These units and their estimated arrival dates are listed in the Time Phased Force Deployment List (TPFDL), Appendix 6, to Annex A to CINCUNC/CFC OPLAN 5027. The TPFDL is updated biennially through U.S./ROK agreements. CINCUNC/CFC OPLAN 5027 is distributed with a SECRET-U.S./ROK classification.

Pyongyang can credibly threaten the prompt destruction of Seoul with conventional arms alone. The North Korean military could also establish a shallow foothold across the DMZ. However, the DPRK's ability to sustain these offensive operations, or advance its forces further to the south, is questionable. South Korean and American air forces could quickly establish air supremacy and destroy North Korean ground forces. The ensuing buildup of US forces in Korea could reverse any remaining North Korean advances into the South, and unlease offensive operations into the North. North Korea does not require long-range missiles with nuclear, chemical, or biological warheads to devastate Seoul or to make a land grab across the DMZ. Such weapons are needed to deter or defeat an American counteroffensive into North Korea.

North Korea has about 500 long-range artillery tubes within range of Seoul, double the levels of a the mid-1990s. Seoul is within range of the 170mm Koksan gun and two hundred 240mm multiple-rocket launchers. The proximity of these long-range systems to the Demilitarized Zone threatens all of Seoul with devastating attacks. Most of the rest of North Korea's artillery pieces are old and have limited range. North Korea fields an artillery force of over 12,000 self-propelled and towed weapon systems. Without moving any artillery pieces, the North could sustain up to 500,000 rounds an hour against Combined Forces Command defenses for several hours.

North Korea's short-term blitzkrieg strategy envisions a successful surprise attack in the early phase of the war to occupy some or all of South Korea before the arrival of US reinforcements on the Korean Peninsula. North Korean ground forces, totaling some 1 million soldiers, are composed of some 170 divisions and brigades including infantry, artillery, tank, mechanized and special operation forces. Of the total, about 60 divisions and brigades are deployed south of the Pyongyang-Wonsan line. North Korea has deployed more than half of its key forces in forward bases near the border. Seventy percent of their active force, to include 700,000 troops, 8,000 artillery systems, and 2,000 tanks, is garrisoned within 100 miles of the Demilitarized Zone. Much of this force is protected by underground facilities, including over four thousand underground facilities in the forward area alone. From their current locations these forces can attack with minimal preparations. This means a surprise attack on South Korea is possible at any time without a prior redeployment of its units.

The North Korean navy has also deployed 430 surface combatants and about 60 percent of some 90 submarine combat vessels near the front line in forward bases. With about 40 percent of its 790 fighter planes deployed near the front line, the North Korean air force could launch a surprise attack on any part of South Korea within a short period of time.

The Democratic People's Republic of Korea possesses larger forces than Iraq, and they are already deployed along South Korea's border. A war could explode after a warning of only a few hours or days, not weeks. Unlike in the Persian Gulf, this attack would be prosecuted along a narrow peninsula on mountainous terrain. It would probably be accompanied by massed artillery fire, commando raids, and chemical weapons. Initially, the primary battlefield would be only about 125 kilometers wide and 100 kilometers deep. The DPRK attack would be conducted against well-prepared ROK forces in fortified positions and against larger US forces than in the Persian Gulf. Most probably, the DPRK attack would aim at seizing nearby Seoul by advancing down the Kaesong-Munsan, Kumwa, and Chorwon corridors. If successful, North Korean forces might also try to conquer the entire peninsula before large US reinforcements arrive.

The South Barrier Fence is the Southern part of the DMZ. The South Koreans have a series of Defensive lines that cross the entire peninsula, but with the exception of the South Barrier Fence, they aren't connected completely across the peninsula. They are designed to withstand an attack and allow a minimum force to hold a line while reinforcement/counter attack forces are assembled and sent to destroy any penetrations.

The basic goal of a North Korean southern offensive is destruction of allied defenses either before South Korea can fully mobilize its national power or before significant reinforcement from the United States can arrive and be deployed. The primary objective of North Korea's military strategy is to reunify the Korean Peninsula under North Korean control within 30 days of beginning hostilities. A secondary objective is the defense of North Korea.

To accomplish these ambitious objectives, North Korea envisions fighting a two-front war. The first front, consisting of conventional forces, is tasked with breaking through defending forces along the DMZ, destroying defending CFC forces, and advancing rapidly down the entire peninsula. This operation will be coordinated closely with the opening of a second front consisting of SOF units conducting raids and disruptive attacks in CFC's rear.

The DPRK offensive against the ROK will consist of three phases. The objective of the first phase will be to breach the defenses along the DMZ and destroy the forward deployed forces. The objective of the second phase will be to isolate Seoul and consolidate gains. The objective of the third phase will be to pursue and destroy remaining forces and occupy the remainder of the peninsula.

Approximately forty percent of the South Korean population resides within 40 miles of Seoul. While the terrain north of Seoul is dominated by rice paddies offering limited off-road mobility, the terrain west of Seoul is a wide coastal plan with the main invasion routes to Seoul. North Korean forces attacking Seoul through the Chorwon or Munsan corridors would have to cross the Han or Imjin rivers (while these rivers freeze in the winter, the ice is not strong enough to support heavy armor). The narrow eastern coastal plain is lightly settled and less heavily defended, though mountains make movement of forces from the east coast difficult.

The US plans are based on the belief that the North Koreans would not be successful in consolidating their gains around Seoul and could be pushed back across the DMZ -- though the plans assume the North may break through the DMZ in places. A critical issue is strategic warning of unambiguous signs that North Korea is preparing an attack. The warning time has reportedly been shortened from about ten days to about three days as North Korea has covered its military activities.

The US-ROK defense plan would be shaped not only by the threat but also by the mountainous terrain. Korea is commonly regarded as rugged infantry terrain that invites neither mobile ground warfare nor heavy air bombardment, but North Korea has assembled large armored forces that are critical to exploiting breakthroughs, and these forces would pass down narrow corridors that are potential killing zones for U.S. airpower. A new Korean War would bear little resemblance to the conflict of 1950­53.

During Phase 1, US-ROK forces would conduct a vigorous forward defense aimed at protecting Seoul. Their campaign would be dominated by combined-arms ground battles waged with infantry, artillery, and armor. US air and naval forces would conduct close air support, interdiction, and deep strike missions. After Phase 1, US-ROK operations in Phase 2 would probably focus on seizing key terrain, inflicting additional casualties on enemy forces, and rebuffing further attacks. Phase 3, to start when the US ground buildup was complete and ROK forces were replenished, would be a powerful counteroffensive aimed at destroying the DPRK's military power. The war plan envisions amphibious assaults into North Korea by US Army and Marines at the narrow waist of North Korea. The entire resources of the US Marine Corps would flow there to establish a beachead, with substantial Army resources quickly conducting over-the-shore operations.

OPLAN 5027-74
The the forward defense strategy in OPLAN 5027 was developed by Combined Forces Commander US General James F. Hollingsworth in 1973 [this discussion is based on "Winning in Korea Without Landmines," by Caleb Rossiter]. Prior to this time, OPLAN 5027 focused primarily on defeating a North Korean invasion. It envisioned the allies staging a 50-mile fighting retreat along the primary armored invasion route from the Demilitarized Zone (DMZ), and taking up strong positions [the "Hollingsworth Line"] south of the broad Han River where it bisects the South Korean capital of Seoul. There, allied forces would wait for US reinforcements before counter-attacking.

Concerned that the US withdrawal from Vietnam might lead the DPRK to question American commitment to defend South Korea, Hollingsworth altered the focus of OPLAN 50-27 to a forward-based offensive strategy. The goal was to convince North Korea that an invasion could bring an end to its regime. The new posture moved most allied artillery, tanks,and infantry forward toward the Military Control Zone (MCZ), which runs five miles south of the DMZ. General Hollingsworth announced plans to strike north after these forces defeated the invasion. He assigned two brigades of the US 2nd Division to seize the North Korean staging city of Kaesong just across the DMZ, and promised around-the-clock raids on the North by B-52 bombers and a “violent,short war ” to capture the capital of Pyongyang.

It was unclear whether Hollingsworth's plans included the use of the US tactical nuclear weapons then on the Korean peninsula if the North Korean invasion forces overwhelmed the allies. At the time, the Congressional Budget Office predicted that without nuclear weapons,the new strategy could result in the initial loss of Seoul. In 1975 Gen. Hollingsworth stated that the US had a '9-day war plan', according to which North Korea would be defeated in a few days in a violent clash with 700-800 air sorties.

OPLAN 5027-94
As of 1994 it was reported that a variant OPLAN 5027 under consideration by CINCPAC focused on a scenario under which ROK forces were able to blunt a DPRK offensive and stabilize a defensive line at FEBA Bravo (20-30 miles below the DMZ). Subsequently, US-ROK Combined Forces Command would execute a retaliatory offensive once US reinforcements arrived. A major air campaign against northern forces would be required before the counteroffensive could begin. A US Marine Expeditionary Force (in division strength) and the 82nd Air Assault Division, along with ROK divisions, would launch an overland offensive north toward Wonsan from the east coas. Soon thereafter, a combined US-ROK force would stage an amphibious landing near Wonsan, and advance to Pyongyang. Subsequently, a combined US-ROK force would execute a major counteroffensive from north of Seoul aimed at seizing Pyongyang. This would be achieved either by linking up with the force at Wonsan, or meeting it at Pyongyang.

A favorable outcome for the South depends on two conditions. First, the ROK forces must withstand DPRK forces during the initial 5-15 days of North Koean offensive actions. Second, they must hold the line while US and ROK forces are mobilized for the counteroffensive, which could take another 15-20 days.

The ROK and US war plan included a counteroffensive that would destroy the North Korean regime. South Korean state television reported on 24 March 1994 that Seoul and Washington planned to topple the North Korean government if the Stalinist state attacks the South. The Korean Broadcasting System said that rather than simply driving back the North’s troops, the plan provides for a counteroffensive to seize Pyongyang and try to topple the government of Kim Il Sung [“KBS reports plan to topple Kim Il Sung,” Washington Times , March 25, 1994, p. 16]. In 1994, the South Korean president, Kim Young-sam, said: “Once a major military confrontation occurs, North Korea will definitely be annihilated” [Ranan R. Lurie, “In a Confrontation, ‘North Korea Will Definitely Be Annihilated,’” Los Angeles Times (Washington Edition), March 24, 1994, p. 11].

The battlefield coordination line (BCL) first appeared in MEF operations during Ulchi Focus Lens (UFL) 94. It was employed as a workaround "MEF internal fire support coordination line (FSCL)" since the combatant commander approved theater FSCL was too distant from the Marine close fight to be of any value. The extended placement of the combatant commander's FSCL was due mostly to cultural and programmatic conflicts between the Army and the Air Force (read JFACC or in Korea, the CFACC). The point of contention has always centered on the area between the FSCL and the ground commander's forward boundary. The Air Force has historically demanded that the Army "coordinate" strikes forward of the FSCL with the CFACC prior to execution. The Army doesn't like the idea of having to coordinate (thus delay operations) with another component inside its own assigned area of operation, so to avoid the problem, they push the FSCL out to a point beyond their area of influence, ATACMS soliloquies notwithstanding. In effect, the FSCL became a de facto forward boundary.

OPLAN 5027-96
After the nuclear crisis of 1994, OPLAN 5027 was completely overhauled, including a new agreement to ensure Japanese bases are available if the US goes to war with North Korea. The updated Japan-US defense cooperation guidelines, which the Japanese parliament approved 24 May 1999, allow the US to prepare for a Korean war by stationing its military forces in Japan and the Pacific region.

OPLAN 5027-98
Further revisions to the concept of operations were elaborated in OPLAN 5027-98, which was adopted in late 1998. Previous versions of OPLAN 5027 had called for stopping a North Korean invasion and pushing them back across the Demilitarized Zone. The new version of the plan was more clearly focused on offensive operations into North Korea. A senior US official was reported to have said: "When we're done, they will not be able to mount any military activity of any kind. We will kill them all." The goal of the revised plan was to "abolish North Korea as a functioning state, end the rule of its leader, Kim Jong Il, and reorganize the country under South Korean control."

New priorities also focused on countering sudden chemical and biological attacks against Seoul. The South Korean military reportedly estimates that 50 missiles carrying nerve gas could kill up to 38 percent of Seoul's 12 million inhabitants.

The new plan called for a campaign against North Korean armed forces and government involving "defeating them in detail." The operation would be conducted in four phases: activities prior to a North Korean attack, halting the initial North Korean assault, regrouping for a counter-attack, and finally a full scale invasion of North Korea to seize Pyongyang.

According to reports, the new military plan included preemptive attacks against North Korea's military bases, including long-range artillery and air forces bases, if intellitence detected a hard evidence that North Korea was preparing to wage war. US and South Korean military leaders included pre-emptive strikes in this revised war plan. If the North Koreans showed unmistakable signs of preparing to strike, and the US decided not to wait until South Korea had been attacked, US forces had targets in North Korea already picked out and weapons assigned to destroy them.

Tasks performed during the Destruction Phase of the OPLAN reportedly involve a strategy of maneuver warfare north of the Demilitarized Zone with a goal of terminating the North Korea regime, rather than simply terminating the war by returning North Korean forces to the Truce Line. In this phase operations would include the US invasion of North Korea, the destruction of the Korean People’s Army and the North Korean government in Pyongyang. The plan includes the possibility of a Marine amphibious assault into the narrow waist of North Korea to cut the country in two. US troops would occupy north Korea and "Washington and Seoul will then abolish north Korea as a state and ‘reorganize’ it under South Korean control.

When this new war plan leaked to the press in November 1998, it escalated tensions between the United States and North Korea. North Korea sharply criticized OPLAN 5027-98, charging that it was a war scenario for the invasion of North Korea. Pyongyang blamed Seoul for the revision of OPLAN 5027, and a North Korean Army spokesman stated 02 December 1998 that North Korea had the right to take a containment offensive while holding mass rallies of military units and various social organizations to criticize OPLAN 5027. Such incidents illustrated North Korea's sensitive reaction to the OPLAN 5027.

On 02 December 1998 the General Staff of the North Korean People's Army (KPA) issued a lengthy and authoritative statement warning that the United States was instigating a new war. The statement stressed that the KPA would rise to the challenge. "We neither want nor avoid a war. If a war is imposed, we will never miss the opportunity," the statement read. The unique aspect of Pyongyang's public statements is the preoccupation with "US war-plan # 5027" as an imminent threat. Official Pyongyang is adamant that "war-plan # 5027" is already being implemented, and public statements frequently focus on OPLAN 5027.

OPLAN 5027-00
According to the 04 December 2000 South Korean Defense Ministry White Paper, the United States would deploy up to 690,000 troops on the Korean peninsula if a new war breaks out. The United States apparently had considerably increased the number of troops that would be deployed in any new Korean conflict. The figure had risen from 480,000 in plans made in the early 1990s and 630,000 in the mid-1990s. The latest Time Phased Forces Deployment Data for any contingency on the Korean Peninsula is comprised of 690,000 troops, 160 Navy ships and 1,600 aircraft deployed from the U.S. within 90 days.

The South Korean defense ministry described the increase as the result of a new US "win-win strategy," which would require the United States to have the capability to fight two wars simultaneously, such as in the Middle East and East Asia. Along with equipment to counter weapons of mass destruction, the US plan focused on the deployment of aircraft carriers and advanced aircraft to attack enemy artillery units in the early stages of any war.

US augmentation forces, including the army, navy, air force, and the marine corps, are composed of approximately 690,000 troops. The augmented forces comprise army divisions, carrier battle groups with highly advanced fighters, tactical fighter wings, and marine expeditionary forces in Okinawa and on the US mainland. The US augmentation forces have contingency plans for the Korean peninsula to execute the Win-Win Strategy in support of United Nations Command (UNC)/Combined Forces Command (CFC) operation plans.

There are three types of augmentation capability: Flexible Deterrence Options (FDOs), Force Module Packages (FMPs), and the Time-Phased Forces Deployment Data (TPFDD). These are executed through a unit integration process, when the commander of CFC requests them and the US Joint Chiefs of Staff orders them in case of a crisis on the Korean peninsula.

FDOs are ready to be implemented when war is imminent. They can be classified into political, economic, diplomatic, and military options. Approximately 150 deterrence options are ready to be employed.

FMPs are measures that augment combat or combat support units that need the most support in the early phase of the war should war deterrence efforts through FDOs fail. Included in the FMPs are elements such as strong carrier battle groups.

Under TPFDD, in which FDO and FMP are included, the key forces are planned ahead of time to be deployed in case of an outbreak of war. There are three types of forces under TPFDD: in-place forces, or forces currently deployed to the peninsula; pre-planned forces, or forces of time-phased deployment in a contingency; and on-call forces, which could be deployed if needed.

CFC Pub 3-1 (Deep Operations ­ Korea) of 1 May 99 requires pre-planned fire support coordination lines (FSCLs) 26 hours prior to ITO execution, and immediate FSCL changes (inside the ITO cycle) 6 hours from transmittal to implementation with nominal FSCL placement 12 to 20 kilometers from the FLOT. The publication discusses the need to avoid confusion and fratricide via frequent FSCL changes, yet still retain the ability to accommodate rapid maneuver. Ground and amphibious force commanders will recommend placement of the FSCL, but the combatant commander is the approving authority.

OPLAN 5027-02
In February 2002 it was reported that the US military was updating OPLAN 5027 in the wake of the September 11 terrorist attacks. This includes a military calculation of the force needed to remove North Korean leader Kim Jung Il.

In mid-2002 a top aide to Secretary of Defense Donald Rumsfeld briefed a concept of operations for striking North Korea's weapons of mass destruction. This case study in the application of the Bush administration's new doctrine of pre-emptive military action envisioned a swift attack, carried out without consulting South Korea, America's ally on the peninsula. Soone after word of the briefing spread, administration officials, including Secretary of State Colin Powell and Adm. Thomas Fargo, commander of US forces in the Pacific, worked to stifle further discussion of the scheme.

OPLAN 5027-04
While Patriot is the only missile defense system deployed by the US military, the Defense Department expects that three "emergency capabilities" for missile defense will begin to emerge in the year 2004. Those capabilities are ground-based midcourse interceptors being installed in Alaska as part of a Pacific test bed; sea-based midcourse interceptors on one or two Navy Aegis ships; and an Airborne Laser prototype. By late 2004 or early 2005 the missile-defense test site at Fort Greely, Alaska could provide an emergency capability against a North Korean missile attack, but it will be extremely limited. Five anti-missile interceptors will be deployed at the site.

Following Operation Iraqi Freedom, USFK held a conference for senior military leaders at Osan Air Force Base to evaluate the air component of OPLAN 5027. The conference was held on May 22-23, 2003 and was to adapt lessons learned from the use of UAVs and ground tactics and to "apply them in plans and strategies for 2003" according to 7th Air Foce commander Lt. General Lance Smith. The Air Boss conference discussed specific targets and the impact of new technologies. According to General Smith, as quoted by Stars and Stripes on May 24, 2003 the battle plan has changed considerably.

In June 2003 US and Republic of Korea officials agreed to a plan to realign American forces stationed in "The Land of the Morning Calm." In June 4-5 meetings held in the South Korean capital city of Seoul, according to a joint U.S.-South Korean statement, it was decided the operation would consist of two phases. During Phase 1 US forces at installations north of the Han River would consolidate in the Camp Casey (Tongduchon) and Camp Red Cloud (Uijongbu) areas. Both bases are north of Seoul and the Han, but well south of the demilitarized zone that separates North and South Korea. The 14,000-strong U.S. Army 2nd Infantry Division, which provides troops to bases near the DMZ, is headquartered at Camp Red Cloud. During Phase 2 US forces north of the Han River would move to key hubs south of the Han River. U.S. and Korean officials agreed to continue rotational U.S. military training north of the Han even after Phase 2 is completed. The realignment operation would take several years to complete.