In the twenty-first century, providing humanitarian assistance to other nations forms an essential part of the U.S. military's mission. Designed to “relieve or reduce endemic conditions such as human suffering, disease, hunger, [and] privation,” the military's humanitarian tasks include such activities as assisting refugees, delivering food and medical equipment to partner nations, and removing unexploded landmines.Footnote ¹ But among the most recognized—and best publicized—of the U.S. Armed Forces’ humanitarian activities are its foreign disaster relief operations. In response to such recent catastrophes as the 2010 earthquake in Haiti, the 2011 tsunami in Japan, 2019's Cyclone Idai in Mozambique, and the 2023 earthquakes in Turkey, the Department of Defense launched extensive humanitarian operations. Taking advantage of the U.S. military's vast global footprint, military leaders dispatched ships and aircraft, service personnel, relief supplies, equipment, and other material and logistical aid to the scene of these crises and to many others like them globally.Footnote ² Carried out for the humanitarian goals of saving lives and reducing suffering, each of these foreign disaster aid operations also shared a critical diplomatic objective: “generating goodwill” for the United States and creating a “favorable impression” of its armed forces.Footnote ³ Never purely altruistic, the U.S. military's responses to global disasters also function as a valuable instrument of contemporary U.S. foreign policy.

The U.S. military has arguably become indispensable to the conduct of U.S. foreign disaster relief operations and to American humanitarian affairs more broadly. But how and when did this come to be? When I first began researching this subject, about a decade ago, I initially assumed these developments had occurred relatively recently, as part of a post-Vietnam or post–Cold War attempt to reinvent and rebrand the armed forces’ mission for the new millennium. Yet in fact, the origins of this humanitarian role stretch back much earlier. Throughout the twentieth century, as the other contributors to this forum explore, the U.S. military has played an integral part in the nation's responses to many global humanitarian crises. Catastrophes caused by natural hazards, as I explore in this essay, were chief among them. Across the first two-thirds of the twentieth century, the U.S. Navy, Army, Marines, Coast Guard, and Air Force conducted scores of foreign disaster assistance operations, their aid reaching all corners of the globe. By the mid-1960s, the U.S. military's humanitarian mission was well-established. In crisis after crisis, it had acted as a first responder to the world.

The U.S. Armed Forces’ long history of involvement in foreign disaster response raises provocative—and some might say troubling—questions about the links between American militarism and American humanitarianism, and their entwined evolution throughout modern American history. Readers of this journal will assuredly be familiar with the basic narrative of U.S. military ascendancy across the long twentieth century. Yet as I argue in this essay, the steady expansion of American military power during these years also had an unforeseen consequence: it enabled the United States to project its humanitarian power more effectively. At the same time, and inversely, the armed forces’ frequent participation in foreign disaster relief efforts helped to legitimize the U.S. military itself in the eyes of both U.S. citizens and many (though by no means all) foreign recipients of its aid. By presenting the military as a benevolent, munificent institution, these operations served to sugarcoat the violence and aggression of its conventional operations. If the U.S. military's strength and capabilities bolstered American humanitarianism during the twentieth century, in other words, American humanitarian operations helped to justify and rationalize U.S. military power. Their relationship was remarkably symbiotic.

The U.S. military's development as an international humanitarian actor occurred in two distinct phases, which mirrored the broader trajectory of U.S. involvement in twentieth-century global affairs. During the first stage, from the late 1890s to the late 1930s, the U.S. government expanded its overseas empire, fought a global war and many smaller conflicts, and bolstered its status as a world power. As part of this process, the U.S. military increased in size and strength, particularly when compared to its nineteenth-century antecedents.Footnote ⁴ These developments carried unintended humanitarian consequences. The addition of personnel, ships, and (eventually) aircraft improved the armed forces’ capabilities not only for war and defense, but also for noncombat operations. With the acquisition of U.S. territories in the Caribbean, the Canal Zone, and the Pacific, the War and Navy Departments established a small network of overseas bases, extending the armed forces’ global reach.Footnote ⁵

Together, these trends enhanced—if inadvertently—the U.S. military's command of humanitarian logistics internationally, building on precedents that had already been established domestically. Throughout the nineteenth century, U.S. Army personnel had engaged in a variety of humanitarian activities within the United States and its continental empire. These tasks included providing disaster relief to U.S. citizens and undertaking medical and sanitation efforts during the Civil War and the American Indian Wars.Footnote ⁶ As the U.S. military's power and capabilities expanded during the early twentieth century, however, its humanitarian reach began to stretch beyond U.S. borders. These developments enabled the armed forces to respond more quickly and vigorously to catastrophes in other nations and to deliver that aid across far greater distances than they had in the past.

Across the first four decades of the twentieth century, spurred by these trends, the U.S. military participated in dozens of disaster assistance operations globally. Following a major earthquake and tsunami in southern Italy in 1908, for example, the U.S. government sent four battleships of the Atlantic Fleet and two other U.S. Navy vessels to the region. They remained there for several weeks while their crews assisted the Italian government in its relief efforts.Footnote ⁷ When catastrophic floods occurred in northeast China in 1917, the Fifteenth U.S. Infantry—then garrisoned in Tianjin—oversaw a variety of humanitarian activities, including most notably the administration of a refugee camp for 4,000 disaster survivors.Footnote ⁸ In 1923, after a cataclysmic earthquake and fires leveled Tokyo and Yokohama, Japan, hundreds of sailors of the U.S. Navy's Atlantic Fleet and U.S. Army personnel from the Philippines, a U.S. territory, converged on the region to assist the Japanese government in its response.Footnote ⁹ Following a major earthquake in Managua in early 1931, U.S. Marines—then occupying Nicaragua—engaged in a multipronged response, which included establishing emergency hospitals and field kitchens, extinguishing fires, clearing debris, and digging graves for the deceased.Footnote ¹⁰ And in 1939, when a powerful earthquake struck south-central Chile, the U.S. military sent three Army Air Corps bombers to the scene, one from the continental United States and the others from the Panama Canal Zone, also a U.S. territory. Designed to carry weapons of war, these planes instead ferried in thousands of pounds of medical supplies, food, and other material aid.Footnote ¹¹

While the foregoing examples illustrate the shape and scope of the U.S. military's foreign disaster assistance efforts during the early twentieth century, they represent only a small sampling of those humanitarian operations. By the eve of U.S. entry into the Second World War, the U.S. Armed Forces had already amassed a long history of responding to international disasters. Between the late 1890s and the late 1930s, American militarism and American humanitarianism had grown increasingly intertwined.

If the foundations of the U.S. military's humanitarian role lay in the early twentieth century, the second phase of its evolution unfolded from the early 1940s through the early 1960s, the apex of the so-called “American Century.” In the process of waging the Second World War, the United States rapidly transformed into a military superpower, a position it maintained as the global Cold War commenced and unfolded.Footnote ¹² Although it was never the primary intention or objective of U.S. policy makers, a secondary effect of this development was to bolster the United States's position as a humanitarian superpower, too.

In mobilizing for these successive conflicts, the U.S. military dramatically—albeit once again unintentionally—increased its capabilities for noncombat operations. From the early 1940s on, the United States controlled or enjoyed access rights to hundreds of military installations throughout the world; hundreds of thousands of U.S. service personnel were now stationed abroad. The military also maintained large stockpiles of rations, medical supplies, and tents, plus vast fleets of ships and aircraft—all of which could easily be repurposed for disaster relief operations. As a result, the U.S. Armed Forces had become exceptionally well positioned to respond to disasters in other nations, wherever in the world those crises might occur. Though the military had regularly responded to international catastrophes during the first forty years of the twentieth century, the majority of American aid during these years had still flowed through nonstate channels, with voluntary organizations and private actors providing a considerable share of overall U.S. humanitarian assistance. The changes set in motion during the Second World War era upended this pattern. By greatly enhancing the military's capacity for delivering aid, these shifts positioned the U.S. Armed Forces to play a far more central—and increasingly essential—role in U.S. foreign disaster response.

The humanitarian implications of these developments became especially evident between the late 1940s and the mid-1960s, as the global Cold War and decolonization together defined U.S. foreign policy calculations and U.S. humanitarian decision making. Across these years, U.S. foreign disaster assistance operations increased in both frequency and scale, with U.S. military forces playing an ever more prominent role in these relief activities. When a major earthquake occurred in Ecuador in 1949, for instance, U.S. Air Force planes from the Canal Zone made seventy-four relief flights to the country, ferrying in large cargos of tents, blankets, medical supplies, and sanitation equipment.Footnote ¹³ Four years later, when a powerful series of earthquakes stuck the Ionian Islands of Greece in 1953, multiple vessels of the U.S. Navy's Sixth fleet swiftly appeared on the scene. They were followed by helicopters and cargo planes, which flew from U.S. bases in Germany and Libya. Eventually, some 10,000 U.S. Navy, Air Force, and Marine Corps personnel traveled to the devastated region to participate in relief activities.Footnote ¹⁴ After another devastating earthquake struck Agadir, Morocco, in early 1960, hundreds of U.S. Navy, Marine Corps, and Air Force personnel participated in the emergency response. They arrived in Agadir from U.S. naval and air bases in Morocco, as well as from the U.S. European Command's Paris headquarters and the U.S. Navy's Sixth Fleet in the Mediterranean.Footnote ¹⁵ Just a few months later, the U.S. military carried out an even larger humanitarian operation in Chile, in response to the May 1960 Valdivia earthquake. In this instance, seventy U.S. aircraft flew to Chile from the Canal Zone, carrying 900 tons of relief supplies in their holds. Arriving with them were 700 U.S. service personnel, who remained in Chile for several weeks to assist in relief activities.Footnote ¹⁶ And in 1963, after an earthquake destroyed Skopje, Yugoslavia, U.S. military aircraft made 100 relief flights to the disaster zone. Their crews brought large quantities of food, hospital equipment, and other aid to the region, transporting these supplies from U.S. bases in Italy, Germany, and the United States.Footnote ¹⁷

These events offer a sense of the military's humanitarian activities in the postwar era; yet once again they represent only a tiny fraction of the disaster relief operations the U.S. Armed Forces conducted during these years. Between the early 1940s and the early 1960s, the U.S. military responded to scores of catastrophes all over the world. Providing international humanitarian aid had become a core element of its mission.

Across the first two-thirds of the twentieth century, the U.S. military thus became a key figure in the delivery, distribution, and administration of U.S. foreign disaster relief. While the United States's ascent from world power to superpower created the material conditions that enabled the military to assume this role, a broad set of diplomatic, strategic, and moral considerations underpinned the decision to use its logistical capabilities for such humanitarian purposes. U.S. policy makers and military leaders saw multiple good reasons to provide the armed forces’ assistance to countries struck by disaster. In addition to ameliorating suffering and helping populations recover from crisis, they sought to build closer ties with other nations, minimize upheaval and unrest, and promote the United States's image on the world stage. Not least, U.S. policy makers hoped to nurture positive views of the U.S. Armed Forces among foreign populations, presenting the military's mission as beneficent rather than belligerent. During these pivotal decades, American humanitarianism and American militarism did not simply coexist; they powerfully reinforced one another in the conduct of U.S. foreign affairs and public diplomacy.

In closing, studying the U.S. military's participation in foreign disaster assistance and other humanitarian crises challenges our understanding of modern American history in fruitful ways. For one, it invites us to acknowledge the blurred boundaries between civil and military actions, hard and soft power, and “wartime” and “peacetime” operations. Exploring these points of overlap is useful not only for historians of the U.S. and the world, but also for scholars working in other subfields of U.S. history, for it highlights the centrality of “the associational state” to the history of American governance writ large.Footnote ¹⁸ Additionally, this history underscores the interdependence of American militarism and American humanitarianism, compelling us to trace their reciprocal evolution more closely. It also forces us to contend with a seemingly paradoxical truth: even as the U.S. military exercised profound violent force during the twentieth century, it simultaneously functioned as one of the United States's most powerful and consequential humanitarian actors. Although we tend to frame American militarism and humanitarianism in rather contradictory ways, viewing these two forces as complementary—and even symbiotic—more accurately reflects the complex nature of U.S. power in the modern world.