The Marines Change Direction (1919-1932)

Battalion: An Organizational Study of United States Infantry

The estate of the late John Sayen has graciously given the Tactical Notebook permission to serialize his study of the organizational evolution of American infantry battalions. The author’s preface and other previously posted parts of this book may be found via the following links:

The 1919 demobilization was nearly as traumatic for the Marines as it was for the Army. Their numbers fell from a peak of 75,000 to about 1,000 officers and 16,000 enlisted in 1920. Authorized strength was 17,400. The 15 Marine regiments and at least three, probably four, machinegun battalions existing at the end of November 1918 had withered away to only five regiments and a couple of separate battalions (one artillery and one infantry) by the following August.

Marine commitments, however, remained heavy. The brigades in both Haiti and the Dominican Republic had their hands full suppressing new rebellions. Guard detachments were still needed for Navy bases and Navy ships. The number of men required for the latter duty had fallen by only 10% since 1918. The Marines also had to staff their own bases at Quantico, Parris Island, and San Diego and they had to find men to rebuild the advance base force as well. When these facts were brought to the attention of Congress in 1920 the latter increased the Marine Corps’ authorized strength to 1,093 officers and 27,400 enlisted but then approved funding for only 20,000.

Actual Marine strength was 1,087 commissioned and warrant officers and 21,903 enlisted in 1922. Enlisted strength gradually fell to 18,000 by 1927 though officer strength actually climbed to 1,198. In 1922, Congress extended the Army’s new seven-pay-grade enlisted rank structure to the Marine Corps and this took effect in 1923. Unlike the Army, however, the Marines did not place specialists in higher pay grades while ranking them as privates. In the Marines, rank and pay went together although rank titles might be changed to reflect specialized occupations.^[1]

A number of cultural and doctrinal changes within the Marine Corps were occurring as well. Uppermost in the minds of many was the question of what the Marine Corps’ future was to be. World War I had done little to answer this since demobilization had placed the Corps in much the same position at the end of the war as the one it had occupied at the beginning, albeit with an enhanced public image and combat reputation.

The bulk of the Corps’ operating forces were still engaged in colonial police work in the Caribbean. However, the new Commandant, Major General John A. Lejeune, was prescient enough to realize that this would not last and that a much more permanent mission would be needed to secure his service’s future. Instead, Lejeune and his advisors concluded that the real mission of the Marine Corps was “readiness.” While this concept might seem trite, one should consider that the United States was and is primarily an insular power. Its standing army in 1920 served primarily as a garrison force and cadre for a much larger wartime citizen army. Little or none of it would be available for immediate use upon the outbreak of a major war beyond the troops already deployed to major US overseas possessions like the Philippines, Hawaii, or the Panama Canal.

Although the Army of 1920 seemed to have little idea about who its future adversaries were likely to be, the Navy had already fingered Japan as its most likely future opponent. Japan had the most powerful navy after the United States and Great Britain and Japanese-American animosity was growing. The Japanese resented the treatment of Japanese immigrants in California. Americans resented Japan’s high handed actions in China. The Japanese saw American criticism of Japan’s China policy as interference in Japan’s rightful sphere of influence. Any war fought against Japan would be primarily naval in character. However, post war disarmament treaties forbade improvements to any American fortresses west of Hawaii. The League of Nations had also mandated most of the central Pacific islands to Japanese control.

If it was to successfully engage the Japanese fleet, or to threaten Japan itself, the United States Navy would need bases in those central Pacific islands. Hawaii was too far away to be useful and the Philippines were too vulnerable to Japanese attack. Only an expeditionary force could seize and hold the central Pacific islands that the Navy needed and that expeditionary force would have to be ready to move whenever and wherever the Navy did. By staying “ready,” requiring only limited reserve augmentation and, being already under the Navy’s control, the Marine Corps would be much better positioned than the Army to provide this expeditionary force, at least during the critical early stages of the next war.^[2]

 A primary exponent of this concept of a future Pacific war was Lieutenant colonel Earl H. “Pete” Ellis, one of the Marine Corps most brilliant and innovative thinkers. Ellis had already written an extensive report in 1912-13 on advance base operations titled “Naval Bases: Location, Resources, Denial, and Security” in which he put forward many of his ideas about overseas operations by (and against) both the Germans and the Japanese. After the war, Lejeune placed him in the planning section that he had set up at Marine Corps headquarters to plan how the Marines would fit into the next war.

In 1921, Ellis completed an extensive study titled “Advance Base Operations in Micronesia” in which he outlined how the Marine Corps might conduct an amphibious campaign against the Japanese. Lejeune heartily endorsed this work and adopted it in toto as Operations Plan 712. In it Ellis discussed the Navy’s need for expeditionary forces to seize and hold island bases in the central Pacific. He described some of the techniques that might be used, including the employment of warships to give gunfire support to a landing force, the role of aviation, and defensive techniques.

Rather than the tactically defensive but strategically mobile version of the Army’s Coast Artillery Corps that it had been prior to World War I, Ellis envisaged a post-war Marine Advance Base Force (ABF) that would be offensively oriented both strategically and tactically. Ellis pointed out that the pre-war assumption that the ABF could seize essential base sites before an enemy could occupy them would not be valid in a war against Japan. The Marines would have to take most of the Navy’s bases by force, often in the face of strong and well-developed defenses, and then defend them against counterattacks. To do this, Ellis proposed an ABF of about 24,000 Marines organized into a base defense brigade and three landing brigades.

Each brigade would have three regiments. The regiments would be assemblies of uniformly configured 125-man companies each of whose training and equipment could vary according to its particular mission. A base defense regiment would include a 300-man air detachment and six companies of coast defense and anti-aircraft guns. A landing regiment would have 12 rifle companies (three battalions) backed by additional companies of machineguns and light artillery.^[3]

Reinforcing Ellis’ ideas were the changes in the Marine officer corps that the First World War had wrought. Instead of having made their careers performing mainly technical duties with the Navy afloat or with the Advance Base Force ashore (as prewar officers had done) many postwar Marine officers were products of their service as infantrymen fighting in a land campaign alongside the Army. Thus Ellis’ concept of a more infantry oriented Marine Corps found itself a receptive audience. Ellis himself did not live to see the results of his work. He died mysteriously in the Palau Islands in 1922 while investigating the illegally constructed Japanese fortifications there.^[4]

Despite Ellis’ untimely death, the Marine Corps lost little time putting Ellis’ basic ideas into practice. With the expectation of getting 27,400 Marines from Congress in 1920, it planned to rebuild its Advance Base Force as the offensively oriented structure that Ellis had advocated. It would have East and West Coast Expeditionary forces.

The East Coast force, based at Quantico Virginia, would be the largest. Its Third Brigade, consisting of the First and Tenth Regiments, would be a base defense brigade, totaling 1,762 enlisted men, plus officers. The First Regiment with a headquarters company, a service company, two searchlight companies (each differently equipped), a signal company, an engineer company, and an anti-aircraft company (armed with machineguns) was the support unit. The newly re-established Tenth Regiment, with three batteries of 75mm field guns and two of 155mm guns, besides headquarters and service companies, was the artillery unit. The Fourth Brigade, a reincarnation of the old AEF brigade and still with the Fifth and Sixth Regiments and Sixth Machinegun Battalion, would be the East Coast landing brigade and was to total 3,575 enlisted men.

The West Coast Expeditionary Force, based at San Diego, had only the Fifth Brigade. It was similar the Fourth Brigade but had only one regiment (the Seventh) and one machinegun battalion (the First). Its enlisted strength was to have been 1,722.^[5

Editor’s Note: The format of the many appendices to this work fit poorly with Substack. For that reason, I have placed them on a PDF file that can be found at Military Learning Library, a website that I maintain.

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^[1] Heinl op cit pp. 228, 315-16, and 611; Clifford op cit pp. 27-30; McClellan op cit p. 17; and Letter from the Major General Commandant to the Secretary of the Navy December 1920, Record Group 127 Ellsdran File 2385-60 US National Archives Washington DC.

^[2] Heinl op cit pp. 253-254; Moskin op cit pp. 219-222; and Clifford op cit pp. 25-29 and 61-64.

^[3] Captain E. H. Ellis USMC FMFRP-45 “Naval Bases: Their Location, Resources, and Security” (Washington DC, HQ Marine Corps  - a reprint 1992 of the original 1913 document made from a photocopy); and Maj Earl H. Ellis USMC FMFRP-46 “Advance Base Operations in Micronesia”  (Washington DC, HQ Marine Corps  - a reprint 1992 of the 1921 original).

^[4] Moskin pp. 221-222; and Heinl pp. 228-229.

^[5]  Letter from Major General Commandant to Secretary of the Navy December 1920, op cit; Letter from the Third Brigade Commander to the Commanding General at Quantico Virginia 6 October 1921 Record Group 127 Ellsdran File 2385-30; Maj L. W. T. Waller, “Machineguns of the Fourth Brigade” Marine Corps Gazette March 1920 pp. 1-31; “Professional Notes - New Tables of Equipment,” Marine Corps Gazette March 1920 pp. 112-113; “Professional Notes - Revision of the Tables of Organization,” Marine Corps Gazette June 1920 p 218.