Small Wars and Big Lessons: 1919–1939

Episode Narrative

In the aftermath of the Great War, the world stood at a precipice, uncertain yet resolute. The year was 1919, an era shaped by triumph and tragedy, where lessons from battlefields were etched into the fabric of military strategy. The U.S. Marine Corps, shifting from the shadows of World War I, began formalizing counterinsurgency tactics in the *Small Wars Manual*. This document wasn’t just another bureaucracy; it was the culmination of experiences drawn from the tumultuous interventions in Haiti and Nicaragua during the 1910s. As the world looked to the future, this manual codified the principles of guerrilla warfare, civil-military relations, and small-unit tactics. These were not mere words on a page but foundational stones that would influence U.S. military doctrine for decades to come.

During this same period, Major General Smedley Butler emerged as a controversial figure. A two-time Medal of Honor recipient, he became a vocal critic of U.S. military engagements in the Caribbean and Central America. Butler saw a disturbing pattern, one in which the use of Marines served corporate interests rather than the patriotic pride of national defense. His denunciation of “war profiteering” echoed through the corridors of military and political power, challenging the very motivations behind countless small wars. Yet, his warnings often fell on deaf ears, drowned out by the clamor for expansion and intervention.

As the decade progressed, international diplomacy sought to prevent another catastrophic arms race. In 1922, the Washington Naval Treaty represented that aspiration. Signed by the United States, Britain, Japan, France, and Italy, it limited naval armaments, capping battleship tonnage while allowing aircraft carriers to flourish. This treaty didn't just reshape naval strategy; it ignited a fervor for innovation and dictated the type of naval warfare the world would come to witness in the decades that followed.

The 1920s bore witness to groundbreaking experiments in naval aviation, with ships like the USS *Lexington* and USS *Saratoga* transformed from battlecruisers into carriers capable of launching aircraft into the sky. These pioneering efforts demonstrated the immense potential of naval air power, significantly influencing future designs and tactics. Each flight launched from those decks was not just an act of testing but a glimpse into the future of naval warfare.

Meanwhile, in the U.S. Army, Brigadier General Billy Mitchell took the mantle of an airpower advocate. Through audacious bombing tests against naval vessels, he proved a fundamental point: aircraft had the power to sink battleships. Yet, Mitchell's bold stance came at a steep price. Facing court-martial for vocally criticizing military leadership, he became a martyr for the cause of air power, a vision that would not be fully accepted until World War II unfolded in all its ferocity.

The backdrop of these developments was the shadow of World War I itself. Between 1917 and 1918, the American Expeditionary Forces deployed over 1.2 million troops to the Western Front. The culmination of their efforts birthed the Meuse-Argonne Offensive, the largest and deadliest battle in U.S. military history, claiming over 26,000 American lives. Yet the horrors of war didn't end with combat; they were compounded by the relentless march of the 1918 influenza pandemic. This devastating wave of illness infected 20 to 40 percent of U.S. military personnel, classifying it as a silent but deadly adversary. The virus, thriving in the crowded camps and chaotic troop movements, would claim more American lives than the battlefield.

Military medical services found themselves on the front lines against this unseen enemy. They deployed early surveillance and quarantine measures for respiratory diseases, marking some of the first systematic responses to a raging epidemic. The methods developed during this crisis would inform public health responses for generations to come. Simultaneously, World War I introduced a new and harrowing facet of warfare: chemical weapons. The U.S. military prepared for gas attacks of chlorine and mustard gas, an unthinkable evolution in the art of war, requiring specialized protective measures to shield soldiers from this new horror.

Despite the advancements in military medicine, infectious diseases like measles still loomed as significant threats to troops stationed in close quarters. As camps crossed the nation housed hundreds of thousands of soldiers, outbreaks became rampant, reminding military leaders that health on the battlefield was as critical as tactical positioning.

In the years that followed the war, the U.S. military began to study its experiences, drawing lessons from both the Great War and the small wars that characterized its engagements in the Caribbean and Central America. Doctrines developed during this period began to emphasize mobility, combined arms, and the intricate coordination between air and ground forces. The anticipation of mechanized warfare loomed large, foreshadowing the conflict and challenges that would dominate the landscape of World War II.

The interwar period marked a significant shift in naval strategy propelled by the limitations imposed by the Washington Naval Treaty. The emphasis on aircraft carriers and naval aviation led to innovative designs that would be pivotal in the Pacific battles that defined the outcome of the next global conflict. The cultural reverberations of World War I also left their mark on American literature and drama. Writers like Eugene O’Neill began to explore the psychological and social effects of war in their works, crafting narratives that examined the souls of soldiers caught in the crucible of a barren battlefield.

Between 1919 and 1939, the U.S. military forged a distinct approach to counterinsurgency, heavily influenced by its experiences in small wars. This emphasis on intelligence, civil affairs, and the judicious use of force became a cornerstone in training manuals that would serve future generations of soldiers. Meanwhile, the advancements in military medicine, spearheaded by figures such as Major General William C. Gorgas, laid the groundwork for improved soldier health based on hard-won lessons from tropical diseases encountered during overseas deployments.

Amid these advancements, the U.S. Navy's experiments with carrier aviation transitioned into a foundation for future operations. Innovations in flight deck operations, arresting gear, and catapult launches began to shape the technological landscape of naval warfare, preparing the U.S. Navy for the challenges that awaited in the unforgiving theater of the Pacific.

Yet, even with all these developments, Billy Mitchell's passionate advocacy for strategic bombing faced institutional resistance. His ideas lingered in the background, waiting for the day when air power would come to be seen as pivotal, not peripheral. The interplay between warfare and disease remained evident throughout this period, as troop movements accelerated the spread of viral infections, highlighting the often-neglected role of public health in military strategy and planning.

The Washington Naval Treaty’s restrictions birthed innovative naval architecture in the U.S., allowing the creation of “treaty carriers” that maximized available tonnage within specified limits. This unique approach to naval strategy forged a new path for the U.S. Navy, solidifying its status as a leading maritime power.

As the decade drew to a close, the hard-earned lessons of small wars began to weave into the fabric of American military thinking. The U.S. Marine Corps’ experiences in these conflicts contributed significantly to the evolution of amphibious warfare doctrine, a critical asset that would later prove decisive in the Pacific Theater of World War II.

Still, as we reflect on this tumultuous decade, one cannot help but ask: What echoes of the past remain with us, and how have they shaped the present? The struggles of Smedley Butler, the vision of Billy Mitchell, the harsh realities of disease and warfare — they remind us that the interplay between military ambition and the dire consequences of intervention is a double-edged sword. In the pursuit of power, what sacrifices must be made, and at what cost? As we move forward, may we take heed of these lessons, striving for a balance that honors the humanity behind the uniform.