The final years of World War I thrust the self-proclaimed isolationist United States onto the world stage. From this new position, the nation recognized a shift in the balance of world power and the potential for a Japanese military threat in the Pacific—and thus the need to acquire, train, and develop a modern amphibious force. As no manual for conducting amphibious landings existed, the Marine Corps set out to create an official doctrine for amphibious warfare. This doctrine became the foundation for World War II’s island-hopping campaign, which in turn led to modifications to the doctrine that enabled the Allies to conduct and win a war in the Pacific.
Ellis’s Brainchild
Long before U.S. entry into World War II, a young, forward-thinking Marine, Major Earl “Pete” Ellis, considered the potential for conflict with Japan. Ellis’s concern grew as Japan expanded into the Pacific and mainland Asia, and he thought it essential for the Marine Corps to transform itself into a modern amphibious force, capable of capturing key island chains to support the forward thrust of the fleet should conflict erupt in the Pacific.
Until this point, it was believed an amphibious assault against a fortified opponent was impossible, given the number of casualties sustained during the British landing at Gallipoli in 1915. However, the Marine Corps intended to change this, focusing on the seizure of advanced island bases in the Pacific.1 Throughout the late 1920s and into the 1930s, the service embraced this new mission and set out to train its forces and establish doctrine in preparation for its execution.2
No existing writing covered or was capable of addressing an amphibious assault against a contested beachhead fortified with modern weaponry. To overcome the logistical and physical challenges such an assault presented, the Marine Corps prioritized full integration of Navy and Marine Corps assets: The landing force would rely on fire and communications support from naval and air assets as it transited to shore. Once the landing force hit the beach, it would rapidly build up force to respond to enemy action.3
After four iterations, in 1934, the Chief of Naval Operations approved the Tentative Landing Operations Manual, which was incorporated into the Navy in 1938 as Landing Operations Doctrine. The Marine Corps now had an official manual for amphibious operations.4
With doctrine established, the Marine Corps was able to evaluate and conduct proper training of its forces. The return of the majority of Marines from Haiti in 1934 enabled numerous military exercises and the men and materials to execute them. Though often crude, these operations were of great value in understanding the readiness of the Marine Corps’ amphibious capability, allowing strategists to develop practical solutions in a simulated environment.5 The exercises showed a promising future for amphibious doctrine, but as late as early 1942, after-action reports described logistical and tactical failures that resulted in unsuccessful landing exercises.6 Despite years of testing, amphibious doctrine was still in its infancy and had never been proven in combat. However, the Japanese attack on 7 December brought to life the scenario Ellis and the Marine Corps had envisioned nearly two decades earlier, and the Fleet Marine Force was soon put to the test.7
Doctrine in Action
The first major test of the amphibious doctrine came in August 1942 at Guadalcanal, the first in a series of amphibious invasions of Japanese-occupied islands.
In preparation for Operation Watchtower, the United States acquired numerous World War I–era civilian shipping vessels, rapidly converting them into troopships. An aging fleet of retrofitted “amphibious assault ships” prepared to launch an array of landing vehicles, ranging from a few modern tracked vehicles to open-top, wooden Higgins boats. After a long and complicated staging process, the landing force was embarked.8
The immediate assault on Guadalcanal was a success, as elements of the Marine landing force made it to shore unopposed. Although impeded by the rough terrain, by the following morning, the force had reached the centerpiece of the island: a Japanese airfield soon renamed Henderson Field. The situation rapidly degraded, however, as shore parties became bogged down on the beachhead, leaving U.S. forces highly vulnerable and with unstable supply lines. The transportation group commander wrote in his after-action report, “Supplies were piling up on the beach faster than could be moved, and by dark there were about 100 loaded boats at the beach and 50 more lying off waiting.”9
Understanding their tenuous position on the island, the Japanese called in aircraft from nearby airfields to respond to the assault, and Japanese naval forces steamed to the area to reinforce ground troops, who had retreated into the jungle. The Americans’ ability to continue unloading operations was reduced significantly. Guadalcanal soon became the site of fierce fighting as Japanese forces attempted to retake their airfield, and the surrounding waters hosted a series of intense naval battles. In all, the battle lasted nearly six months, concluding in early February 1943 with the withdrawal of the Japanese troops.10
U.S. landings at Guadalcanal did not come without cost. Nearly 1,600 men were killed during the battle, multiple ships and aircraft were lost, and the United States was left with only a single aircraft carrier in the Pacific theater. The Marine Corps had proven itself and its amphibious doctrine—but not without complications. While many of the challenges at Guadalcanal were unavoidable, the improper execution of concepts outlined in the amphibious doctrine was not.
Lessons Learned, Changes Made
One of the largest failures was in unloading operations. The doctrine lacked a definitive command-and-control structure, leading to a chaotic offloading effort ashore, exacerbated by Japanese counterattacks.11 Lack of coordination in offloading operations inhibited the early progress of the shore party, and it became obvious that adjustments to the doctrine were needed to prevent such issues in successive landings.12
However, the amphibious doctrine and the majority of its fundamental principles endured, and the Navy and Marine Corps team that made up the invasion force made incredible advances despite the early setbacks. The Marines who implemented the doctrine at Guadalcanal were presented with an unproven concept, regardless of years of rehearsal and thoughtful planning. Their ability to set practical expectations under real operating conditions contributed to the ultimate success of Operation Watchtower.13 During the battle, the Marine Corps looked closely at its use of landing vehicles, the organization of forces, and the speed of operations. Logistical challenges needed to be ironed out, and a clear command-and-control structure had to be defined. Continued success in the island hopping campaign required more efficient ship-to-shore movement and the rapid buildup of force on shore.14
Following the doctrine’s first trial by fire, the Marine Corps implemented a series of changes to correct the failures at Guadalcanal, better support the flow of operations, and accommodate improvements in capability of the Navy and Marine Corps.15 In addition, as the war progressed, U.S. industrial capability began to outpace that of Japan. The Marine Corps could now rely on purpose-built landing craft and transport ships to carry its troops into combat.
With each subsequent assault and victory, the capability of the Fleet Marine Force grew, as air and naval gunfire support reigned supreme in both preparation for the assault and support of the landing. A flexible command-and-control element was aided by innovations in communication, allowing a landing force to rapidly coordinate offloading operations even while under fire.16 Lessons learned at Guadalcanal provided the basis for modifications to the amphibious strategy, which, in combination with increased production capability, created an incredibly lethal landing force for the remainder of the war.17
Throughout the war in the Pacific, the revised amphibious doctrine continued to receive updates based on the results of combat operations. These developments set in motion a U.S.-led momentum that propelled the Allies through the Pacific. The strength of the U.S. fighting machine was unrivaled by the Japanese and reinforced by the efficient integration of Marine divisions and air wings and improved tactics and adapted weaponry.18 The culminating event of the Marine Corps’ World War II amphibious campaign was the Battle of Okinawa, one of the largest amphibious operations in history. Victory at Okinawa provided the final staging point for the invasion of mainland Japan, a strike intended to end the war. Ultimately, Allied leaders determined the projected casualties were unjustifiable, and the final action of the war was not the planned amphibious assault. However, the ability of the Marine Corps’ amphibious doctrine to endure a four-year island hopping campaign involving operations of all scales proved its adaptability and the brilliance in its creation.19
The World War II island hopping campaign was a proving ground for amphibious doctrine. Shortcomings discovered during combat operations led to modifications that improved the tactical, logistical, and support structures of the amphibious landing force and allowed for the successful advance of Allied forces toward Japan’s home islands.
Today, amphibious landings remain an indispensable capability of the U.S. military, and the Marine Corps continues to rely on an amphibious doctrine based on the same fundamental principles introduced prior to and improved during the Pacific campaign. Just as then, the doctrine continues to be modified to meet the demands of the modern battlefield, undergoing a significant revision to address the potential threat provided by today’s near-peer rivals.
1. Richard B. Frank, “The Amphibious Revolution,” Naval History 19, no. 4 (August 2005).
2. LtCol Frank O. Hough and Maj Verle E. Ludwig, USMC, and Henry I. Shaw Jr., “Evolution of Modem Amphibious Warfare, 1920–1941,” in The Legacy of American Naval Power: Reinvigorating Maritime Strategic Thought, ed. Paul Westermeyer (Quantico, VA: Marine Corps History Division, 2019), 45.
3. Hough, Ludwig, and Shaw, “Evolution of Modern Amphibious Warfare,” 53.
4. Douglas E. Nash, “Origins of the Gator Navy: Amphibious Shipping in Support of Landing Operations,” Fortitudine 38, no. 2 (2014): 8.
5. Richard B. Frank, “Innovation and Determination Ashore,” Naval History 21, no. 4 (August 2007).
6. MajGen Holland M. Smith, USMC, “Preliminary Report of JANEX-1,” in The Legacy of American Naval Power, 74–85.
7. Hough, Ludwig, and Shaw, “Evolution of Modern Amphibious Warfare,” 53–61.
8. Frank, The Amphibious Revolution.
9. David C. Emmel, “The Development of Amphibious Doctrine,” master’s thesis (U.S. Army Command and General Staff College, 2010).
19. David O’Hora, “Defense in the Pacific, 1937–1943,” in Sea Power and the World, ed. James C. Bradford (West Sussex, UK: John Wiley and Sons, 2016), 210–24.
11. CDR Eric Shuck, USNR, “Shoestring Logistics Lessons from Guadalcanal,” U.S. Naval Institute Proceedings 45, no. 11 (November 2019), 38.
12. O’Hora, “Defense in the Pacific,” 210–24.
13. Jon T. Hoffman, “The Lessons and Legacy of Operation Watchtower,” in The Legacy of American Naval Power, 71.
14. Frank, "Innovation and Determination Ashore."
15. Frank M. Benis and Henry J. Shaw Jr., History of U.S. Marine Corps Operations in World War II, vol. 5 (Washington, DC: Historical Branch, G-3 Division, Headquarters U.S. Marine Corps, 1968), 666.
16. Benis and Shaw, History of U.S. Marine Corps Operations, 658–74.
17. William F. Trimble, “Offensive in the Pacific, 1943–1944,” in America, Sea Power, and the World, ed. James C. Bradford (West Sussex, UK: John Wiley and Sons, 2016), 225–41.
18, Benis and Shaw, History of U.S. Marine Corps Operations, 676.
19. Edward J. Marolda, “The Victory of Sea Power in the Pacific,” in America, Sea Power, and the World, 242–58.