The Pacific theater of World War II witnessed the introduction of a number of new joint operational concepts providing lasting lessons to today’s warfighter. At the Battle of Midway, carrier-based aircraft conducted the first major fleet engagement entirely beyond visual range of the battle group. The doctrine of joint amphibious-assault operations was refined during the island-hopping campaign, which spanned the Philippines to the Bonins. Although a relatively new term in joint parlance, operations in the Pacific Theater demonstrated the concept of joint operational access (JOA). Operation Forager—the 1944 American invasion of the Mariana Islands and Palau—is an example of U.S. military efforts to achieve JOA to the Japanese mainland, and it offers relevant insights into the recently developed Joint Operational Access Concept (JOAC) of today.
Dueling Strategies, Common Goal
During a series of conferences in 1943, military planners agreed on the main strategic principles for bringing about the unconditional surrender of Japan. Initially, the Army commander in the Pacific, General Douglas MacArthur, and the Chief of Naval Operations, Admiral Ernest King, held starkly different views of the Pacific campaign strategy. On the one hand, Admiral King favored a drive into the Central Pacific, which specifically focused on an advance through the Marshall Islands and the eventual capture of the Mariana Islands—Saipan, Guam, and Tinian. On the other hand, MacArthur preferred to continue operations in the Southwest Pacific, with the focus on New Guinea and ultimately the Philippines—likely in an effort to make good on his famous pledge to return after his escape from Corregidor in March 1942. MacArthur openly objected to King’s Central Pacific plan, and he protested directly to the Joint Chiefs. In August 1943, during the First Quebec Conference (codenamed “Quadrant”), the Combined Chiefs decided to make the Central Pacific campaign the main effort and the Western Pacific campaign the supporting effort, despite MacArthur’s objections.1
Also during the Quadrant Conference, the U.S. Army Air Forces commander, General Harold “Hap” Arnold, shared his “Air Plan for the Defeat of Japan,” where he delivered the estimate that the Army Air Corps would have ten groups of a new long-range bomber, the B-29 Superfortress, by October 1944. The Army Air Corps anticipated the B-29 to have an operational radius of approximately 1,750 miles—though planners would reference 1,500 miles due to operational efficiency and safety. Planners and commanders did not believe that an island’s capture within 1,500 miles of the Japanese homeland would occur in time for the bomber’s introduction, and the alternative—using airfields in mainland China—was particularly unpalatable. Therefore, after the conclusion of the conference Army Air Forces planners advocated the seizing of the Marianas by mid-1944, because “plans for the acceleration of the defeat of Japan would place emphasis upon the seizure of the Marianas at the earliest possible date, with the establishment of heavy bomber bases as the primary mission.”2
It was during the last conference (codenamed “Sextant”) in December 1943 that commanders approved the final strategy. The “Overall Plan for the Defeat of Japan” was a simultaneous, two-pronged drive through the Central Pacific and the New Guinea/Dutch Indies/Philippines axis. The goal was “to obtain objectives from which we can conduct intensive air bombardment and establish a sea and air blockade against Japan, and from which to invade Japan proper if this should prove necessary.”3
Thus, U.S. planners realized the strategic importance of the Northern Marianas, as the islands were critical for extending operational reach in the Pacific. At the same time, the Japanese attempted to employ anti-access/area-denial (A2/AD) to prevent U.S. forces from achieving joint operational access to the Japanese mainland. Prior to understanding the Japanese Empire’s use of A2/AD in the Northern Marianas campaign, it is essential to first achieve an understanding of A2/AD as a concept.
Anti-access describes the actions taken, usually at long range, designed to prevent opposing forces from entering an operational area, and area denial encompasses those actions, usually at shorter ranges, to limit an opposing force’s freedom of movement within an operational area. The Air-Sea Battle concept is an evolution of traditional U.S. power projection that focuses on developing integrated air and naval forces to degrade and neutralize an adversary’s A2/AD threat to ensure freedom of movement for friendly forces. Accordingly, the A2/AD JOAC is not new—the contest for operational access can even dominate all other considerations in warfare, as it did throughout the Pacific Theater.4 Addressing the threat posed by adversaries with A2/AD capabilities presents a complex challenge to how joint forces operate, which the Japanese employment of A2/AD concepts during the Northern Marianas campaign further illustrates.
The Japanese established the National Defense Zone, or “Tojo Line,” in September 1943 after losing eastern New Guinea and the Solomons to the Allied advance. Imperial Japan’s defense strategy in the Mariana Islands sought to marshal, service, and supply its 4th Fleet air and naval forces to enable them to launch raids and small-scale operations out of range of Allied bases and reconnaissance aircraft. This would buy them time as the Japanese Combined Fleet sortied to meet and defeat the approaching U.S. fleet in a decisive battle before U.S. forces could reach the Japanese mainland.5 Until the eve of the U.S. initial assault into the Southern Marianas on 22 February 1944, the Japanese worked feverishly to improve their beach defenses through the Mariana Islands chain—particularly near Tinian Town and Asiga Bay—which Japanese intelligence assessed as the probable landing beaches for the U.S. invasion.6
Thereafter, Japan’s operational approach in the Marianas campaign in 1944 remained unchanged—to employ air power against the U.S. Navy surface combatants and use kamikazes as means of long-range antiship attack. Indeed, Japanese leaders viewed control of the land, seas, and skies in and around the Marianas as a decisive point in halting the American momentum.7 Up until this point, Japan’s naval and air forces’ use of long-range antiship warfare had slowed the progression of the U.S. Navy’s island-hopping campaign by increasing the risk of catastrophic losses as ships moved closer to the Japanese mainland.8 Despite their strategic importance to the home islands, the Japanese war efforts in the Marianas were futile due to inefficient sustainment and halted reinforcements as a result of coordinated U.S. naval and air bombardments of coastline defenses, coupled with an integrated ground effort from the Army and Marines. The fall of Saipan and Tinian was a turning point in the Pacific war, as it provided for the forward basing of atomic strikes on Hiroshima and Nagasaki and ultimately led to the resignation of Japanese Prime Minister Hideki Tojo and his cabinet.9
Accordingly, when advocating in favor of a joint approach to countering current and future A2/AD threats, a review of U.S. operations in the Pacific theater of World War II provides an understanding that the United States should seek unity of effort in employing a joint, interagency, intergovernmental, or multinational approach to overcoming A2/AD challenges.10
JOA Precepts in Forager
Signed by Chairman of the Joint Chiefs of Staff General Martin Dempsey in January 2012, the JOAC represents the most recent attempt by the U.S. defense community to develop the “ways” that counter an adversary’s use of A2/AD against U.S. military power. The Mariana Islands, as the primary objective for Operation Forager, were a key foothold for the Japanese Empire’s defense of mainland Japan. The islands and the Japanese forces based in and around them were part of an A2/AD system designed to prevent U.S. access to the Japanese home islands.
As currently envisioned, the JOAC identifies operational-access precepts for planners to use to effectively defeat adversary A2/AD capabilities and achieve access into denied spaces. While the JOAC is a modern document, the planning and execution of Operation Forager applied many of the underlying precepts of operational access against enemy A2/AD.
The first precept is to conduct operations to gain access based on the requirements of the broader mission, while also designing subsequent operations to lessen access challenges. These operations are part of a broader plan and should not move farther into an adversary’s A2/AD system than needed.11 Operation Forager was part of a larger U.S. effort aimed at defeating the Japanese Empire via a route through the Central Pacific under the command of Admiral Chester Nimitz. At the same time, General MacArthur was moving from Australia toward the Philippines in the Western Pacific. Securing the Mariana Islands achieved two objectives. First, the island chain represented the initial break in the outer Japanese defenses. Second, the United States would have an “unsinkable aircraft carrier” within B-29 Superfortress striking distance of the Japanese mainland.12
Taking the Marianas from the Japanese required significant advanced preparation to facilitate U.S. access to the operational area. This included the reduction of Japanese positions in the Marshall Islands chain and the neutralization of the Japanese fleet based in Truk. These operations occurred in January and February of 1944 and enabled the Joint Chiefs of Staff to order the seizure of the Marianas in June of 1944.13
The third precept calls for the consideration of a variety of basing operations. The Pacific consists of vast expanses of ocean dotted with multiple options for basing an invasion force. The capture of the Eniwetok Atoll in mid-February 1944 permitted the forward marshaling of Joint Expeditionary Forces for the Marianas invasion. Additional troops from Hawaii could also be staged at Eniwetok prior to moving on to the Marianas.14
The fourth precept of Joint Operational Access is seizing the initiative. At the strategic level, the United States was moving against the Japanese Empire along two main avenues of approach. The main effort led by Admiral Nimitz was advancing through the Central Pacific toward the Japanese mainland. The supporting effort was in the Western Pacific under the command of General MacArthur. The decision to move on the Marianas exemplifies the concept of seizing the initiative. The early seizure of U.S. objectives in the Marshall Islands along with the fall of Eniwetok and defeat of the Japanese fleet at Truk enabled the Joint Chiefs to order follow-on operations in the Marianas ahead of schedule. The decision to move quickly, along with targeting of Japanese troop transports, prevented the reinforcement and defensive preparations of the island chain.15
The Joint Expeditionary Forces achieved local domain superiority during a number of key engagements throughout the course of the Marianas campaign. The defeat of the Japanese navy at Truk and the Battle of the Philippine Sea removed Japanese naval and air threats against U.S. invasion forces. The United States used its recently acquired advantage in sea power and naval aviation to counter the sealift of Japanese ground forces throughout the area of operations and deny Japan’s freedom of movement between islands. Japan was unable to shift combat power or military equipment around its Pacific holdings in late 1943 and 1944 without significant losses through interdiction by U.S. naval forces.16
Maneuver against operational objectives from a strategic distance was difficult in the Pacific theater. Naval, air, and ground operations required large and cumbersome logistics tails. This necessitated the invasion of a number of island chains that U.S. forces could otherwise bypass in a similar situation today. Just as the capture of Eniwetok had enabled the forward staging of forces from Hawaii prior to the Marianas landings, the Marianas invasion enabled the forward staging of supplies for future landings at Iwo Jima and Okinawa and the planned invasion of Japan.
Operational Access in Today’s Pacific
Those A2/AD and JOAC concepts critical to World War II campaigns continue to influence current operations in the Pacific today. Today, the Chinese concept of defending along a first island chain and a second island chain is eerily reminiscent of Japan’s defensive strategy in World War II—and both are examples of A2/AD. Technology has increased the range and lethality of modern weapon systems compared to their 1940s equivalents. Space and cyber domains have added layers of complexity to the operational environment. The ability to attack directly from strategic bases affords China greater opportunities and flexibility in targeting adversaries across the operational spectrum and from longer distances.
China’s employment of the A2/AD concept in deterring and defeating a sophisticated adversary (like the United States) from third-party intervention in a potential Taiwan Strait scenario consists of encumbering U.S. military access to the Asian theater. Over the past few decades, China has pursued a variety of air, sea, undersea, space and counterspace, information-warfare systems, and operational-approach concepts, cultivating an array of overlapping, multilayered offensive capabilities extending from China’s coast into the Western Pacific.17 Specifically, this approach includes attacking U.S. command, control, communications, computers, intelligence, surveillance, and reconnaissance systems; attacking sustainment and transportation hubs; attacking air bases within the area of operations; blockading and attacking sea lanes and key ports; attacking aircraft carriers; and preventing the use of bases on allied territory, primarily those in mainland Japan and Okinawa.18
Above all, the one thing that remains unchanged is the strategic geography of the Pacific Ocean and the importance of controlling access into one’s home waters through advanced weapon systems (e.g., aircraft carriers, long-range missiles, cyber) and the occupation of key bases and island chains (e.g., Okinawa, Guam, Hawaii) to enable offensive and defensive operations. The speed and pace of warfare may change, the specific weapon systems may be different, but the overarching concepts remain the same.
China’s current use of A2/AD and U.S. advancement of JOAC precepts exemplify the continued evolution of these warfare concepts seen in the Pacific theater of World War II. Accordingly, A2/AD and JOAC are really not new principles, but are merely the application of new systems and capabilities to the tried and true precepts of warfare in general.
1. Philip A. Crowl, United States Army in World War II: The War in the Pacific—Campaign in the Marianas (Washington, DC: Office of the Chief of Military History, 1960), 11.
2. Ibid., 12.
3. Ibid., 13.
4 Department of Defense, Joint Operational Access Concept (JOAC) (Version 1.0), I, 4–5.
5. Gordon L. Rottman, Saipan & Tinian 1944: Piercing the Japanese Empire (Oxford, UK: Osprey, 2004), 9, 18–19.
6. Crowl, United States Army in World War II, 282–83.
7. Victor Brooks, Hell is Upon Us: D-Day in the Pacific, June–August 1944 (Cambridge, MA: Da Capo Press, 2005), ix.
8. Vincent Alcazar, “Crisis Management and the Anti-Access/Area-Denial Problem” Strategic Studies Quarterly, vol. 6, no. 4 (Winter 2012), 49.
9. D. Colt Denfeld, Hold the Marianas: The Japanese Defense of the Mariana Islands (Shippensburg, PA: White Mane, 1997), xii.
10. John Gordon IV and John Matsumura, The Army’s Role in Overcoming Anti-Access and Area-Denial Challenges (Santa Monica, CA: RAND, 2013), x.
11. JOAC, 18.
12. Crowl, United States Army in World War II, 9, 11.
13. Rottman, Saipan & Tinian, 12.
14. Brooks, Hell is Upon Us, 78.
15. Rottman, Saipan & Tinian, 43.
16. Ibid., 20.
17. Office of the Secretary of Defense, Annual Report to Congress: Military and Security Developments Involving the People’s Republic of China, 32.
18. Gordon and Matsumura, The Army’s Role, 51.
Commander Gustin is currently serving as a legislative-affairs officer for the Commander North American Aerospace Defense Command and U.S. Northern Command in Washington, D.C. He previously served as a department head in Strike Fighter Squadron Two One One, Naval Air Station Oceana, Virginia Beach, Virginia.
Major Gibbons is currently serving as a military intelligence analyst at the Defense Intelligence Agency. He previously served in the Intelligence, Surveillance, and Reconnaissance Directorate of the U.S. Forces Korea J2 Staff, U.S. Army Garrison Yongsan, Seoul, Republic of Korea.
Operational Access Precepts
- Conduct operations to gain access based on the requirements of the broader mission, while also designing subsequent operations to lessen access challenges.
- Prepare the operational area in advance to facilitate access.
- Consider a variety of basing options.
- Seize the initiative by deploying and operating on multiple, independent lines of operations.
- Exploit advantages in one or more domains to disrupt enemy anti-access/area-denial capabilities in others.
- Disrupt enemy reconnaissance and surveillance efforts while protecting friendly efforts.
- Create pockets or corridors of local domain superiority to penetrate the enemy’s defenses and maintain them as required to accomplish the mission.
- Maneuver directly against key operational objectives from strategic distance.
- Attack enemy anti-access/area-denial defenses in depth rather than rolling back those defenses from the perimeter.
- Maximize surprise through deception, stealth, and ambiguity to complicate enemy targeting.
- Protect space and cyber assets while attacking the enemy’s space and cyber capabilities.