In the 1920s, aviation was a technology largely untested in warfare. Though it had seen sparse action during World War I, its impact in warfare remained largely unknown by most militaries around the world—and the U.S. Marine Corps was no exception. Nonetheless, instability in the Caribbean led to frequent and sustained interventions by the Marine Corps, including a counterinsurgency campaign in Nicaragua. The Second Nicaraguan Campaign (1926–33) provided the perfect opportunity for the service to field and experiment with a recently developed technology, leading to groundbreaking innovations in both tactics and procedures later applied in World War II.
Similar to the Second Nicaraguan Campaign, the conflict between Russia and Ukraine provides an opportunity for the United States to test and experiment with its recently developed technologies that have not been employed in combat. The lessons gleaned from and improvements made to these technologies could prove invaluable should the United States ever find itself involved in a larger-scale conflict against Russia or China.
Novel Technology for a Tough Terrain
By 1927, 4,000 Marines were battling a counterinsurgency campaign in Nicaragua.1 As a result of the strong efforts of Henry Stimson, a special envoy sent by the Coolidge administration to resolve the civil war between the Liberal and Conservative forces, the so-called Tipitapa Agreement was reached after a month of negotiations.2 The Liberal forces agreed to lay down their arms and surrender their weapons for monetary compensation, with the understanding that the United States would station Marines to host and supervise a new presidential election in 1928.3
All the Liberal general officers followed the agreement, except for Augusto César Sandino. He deplored U.S. imperial influence in Nicaragua and resolved to fight against U.S. intervention. Sandino and his followers launched a deadly insurgency against the U.S. Marines, hiding among the populations in Nicaragua and attacking the Marines when they least expected it. In addition, Nicaragua’s terrain was rough and mountainous, and the country lacked the developed infrastructure typically needed to fight and supply troops, presenting challenges to the Marines. By 1927, the United States had sent in not only thousands of Marine riflemen to quell the Sandino insurgency, but also dozens of aircraft—a novel technology that had seldom been used in battle before.
In Nicaragua, the development of ground-to-air communications was displayed most prominently in the Battle of Ocotal. During the campaign in Nicaragua, radio was still in its infancy. Moreover, the lack of proper equipment at ground stations and on aircraft, along with heavy atmospheric conditions, interfered greatly with the reception and transmission of voice.4 To resolve this issue, the Marine Corps developed three novel ways to communicate with ground forces. First was the message drop-off: The Marines devised a method to precisely drop messages in weighted bags from the cockpit of an aircraft for receipt by ground forces.5 Second, they implemented an ingenious method for picking up a paper message, whereby ground forces hung a message in a bag between two wires, while an aviator flew low with a weighted rope to “catch” the message.6 Third, they devised a system of ground signal panels. With these panels Marines could explain in simplistic terms, using large block letters, shapes, and numerals, what the situation was on the ground.7
The use of aviation in combat exposed the issue of communication, which the Marine Corps swiftly resolved to maintain combat efficiency. The use of these novel communication methods was pivotal in the outcome of the Battle of Ocotal and greatly improved the lethality of aviation.
On 16 July 1927, two pilots flew over a Marine Corps garrison in Ocotal, deep inside Nicaragua. Looking down, they noticed the lack of signal panels along the runway for aviators to read. Increasingly suspicious, the pilots looked further, and near a courtyard they found signal panels that read, “Am being attacked by Sandino. One dead, several wounded. Need assistance.”8 With this knowledge, the aviators flew back to their base in Managua, the capital of Nicaragua, and immediately launched three more aircraft to relieve the Marines. As the aviators approached, they launched bombs and gunned down several of Sandino’s forces, accomplishing “for the first time in military annals, the relief of a beleaguered town by air.”9
A similar situation occurred in February 1928, as Marines pursued the insurgents. Aviators spotted a friendly ground patrol being overrun and initially dropped “provisions and water to the Marines.” In response, the ground patrol laid out panels “indicating the direction and range of the enemy and requesting an air attack.” The aviators received the message and attacked accordingly, in “the first known case of an air attack being directed by ground troops.”10
These two engagements highlight the aviation innovation that took place in Nicaragua. Combat in Nicaragua was the catalyst that led to Marine aviators recognizing an issue with communication. The resultant revolutionary developments of air-ground communication techniques began to show the full potential of aviation in warfare, which would be used to the highest extent in World War II.
Air Delivery for Distant Bases
Another significant improvement to Marine Corps aviation came in the form of transport planes. To adapt to the rough terrain in Nicaragua, the Marines sought to use aviation as an alternative to supply ground forces throughout the country. They initially had to use observation planes, which were not designed to carry a heavy load of supplies.11 After a few notable incidents, including one in Ocotal in which an aviator had to make ten round trips to drop off supplies and take the wounded to safety, the inadequacies of the observation plane began to show.12 Heavyweight loads were not possible, requiring frequent trips, and the number of personnel who could be carried on board was very limited. The Marines decided that to maintain all their bases within Nicaragua, a new aircraft was needed.
By December 1928, the Marine Corps had received four Fokker transports, a significantly larger and more stable aircraft, designed specifically for transportation.13 The Fokker not only could carry more supplies and men than previous aircraft, but also was not limited by runway size—a common issue when observation planes were used to transport heavy loads.14 As the campaign progressed, these transportation planes began to carry an ever-increasing share of the supplies, becoming an essential asset for the Marines operating in Nicaragua.
Furthermore, these aircraft showed the possibility of supplying distant bases almost entirely by air, requiring neither roads nor railroad tracks to complete the mission. During World War II, transportation planes would become even more essential in connecting far-flung Pacific islands and maintaining critical lines of communication.
Fine-Tuning a Deadly New Aerial Tactic
The improvements to aviation warfare included new offensive tactics, notably dive-bombing. Before the campaign in Nicaragua, bombs were dropped while the aircraft flew nearly horizontal. The main issue was accuracy: with slight winds or if the timing of the drop was not exact, the bomb was likely to land far from the target. However, many aviators were hesitant to change their tactics because they feared diving would leave their aircraft far “too vulnerable to antiaircraft artillery.”15 As the need for accuracy—to provide closer air support—outweighed the increased vulnerability of the aircraft, aviators began experimenting with dive-bombing. Initially, aviators would begin their dives at 1,500 feet and pull out at 600 feet. As they improved their technique, they eventually dove at 1,000 feet and pulled out at 300 feet, far closer, and consequently more accurate, than before.16
As the intervention in Nicaragua progressed, dive-bombing became the primary method for dropping ordnance because of its high accuracy. On numerous occasions, Marine aviators were able to target areas much closer to Marine ground forces without fear of accidentally hitting friendly forces. Moreover, the development of this new offensive aerial tactic shows how essential the campaign in Nicaragua was for the Marine Corps to learn the full potential of aviation in warfare. The campaign provided Marine aviators the opportunity to experiment and innovate, leading to far more effective offensive tactics, such as dive-bombing. Not only that, but the Marines also “proved the efficacy of dive-bombing in the role of close air support,” which would be heavily implemented in the Pacific.17 The experience and techniques for dive-bombing, learned through combat in Nicaragua, made aerial attacks and close air support more effective during World War II.
Groundbreaking Manuals on Doctrine
Not only did the Marine aviators innovate technologically and tactically during the campaign in Nicaragua, but they also formalized their findings through the development of doctrine. Major Ross E. Rowell, one of the most prominent aviators who served in Nicaragua and a prolific writer in The Marine Corps Gazette about his experiences, was a key contributor to the development of air doctrine. He wrote two articles outlining the aforementioned improvements—including ground-air communications, the transportation plane, and dive-bombing. In addition, he wrote about practical matters such as the best altitude at which to fly, how to spot Marines in trouble without making contact, and the signs of an enemy camp.18
Captain H. Denny Campbell also wrote in the Gazette about his experience, reiterating Rowell’s advice and supporting it with his own personal anecdotes from his time in Nicaragua.19 These articles contributed significantly to the improvement of aviation warfare, but they also served as a forum for the aviators to establish the best practices and most efficient methods for using aircraft, which were established with the publication of the Small Wars Manual in 1940.
The Small Wars Manual was published as a way for the Marine Corps to establish a standard procedure for operating in low-scale conflicts, serving to consolidate the lessons learned from operations in Nicaragua and throughout the Caribbean. Though the manual focuses heavily on the ground tactics and political implications of certain military procedures, it also includes a dedicated chapter on aviation warfare. This chapter is broken into seven subsections, describing everything from aviation transportation, ground communication, combat support and reconnaissance to how to manage and prepare bases and landing fields.
These sections are replete with lessons taken directly from the campaign in Nicaragua. The section on transportation planes, highlighting the importance of air transport as a campaign moves inland and when there are no “navigable rivers and railroads,” came directly from the Marines’ experience in Nicaragua.20
Similarly, the section on combat support, which describes “attacks on towns” and how to avoid civilian casualties, was a lesson from the Marines Corps’ experience in the Battle of Ocotal.21 These lessons proved invaluable only a few years after their publication, with the onset of the World War II. Experience in Nicaragua taught aviators crucial skills, changing many ways aviation was implemented and leading to a far more effective use of the new technology. The campaign in Nicaragua was fertile ground for the cultivation of aviation doctrine, formalized with the publication of the Tentative Landing Operations Manual (TLOM) in 1938, in addition to the Small Wars Manual.22
Similar to the Small Wars Manual, the TLOM includes an entire chapter on aviation, further subdivided into nine sections. These sections cover communication, bombs, and air bases, to name a few, most of which apply lessons derived from the Marines in Nicaragua. The section on bombs, describing bomb weights, is taken directly from Nicaragua.23 While the Marines were initially given 50-pound fragmentation bombs, Major Rowell suggested they use much smaller ordnance. He suggested that a 25-pound fragmentation bomb, half the weight of the initially issued bomb, would be more effective. More bombs could be dropped, increasing the area affected, while still inflicting significant damage on Sandino’s troops and supplies.24
Moreover, in the section on air bases, many of the lessons, such as how to choose the location for airdromes, came from Nicaragua.25 The Marine Corps faced challenges there when deciding on locations to place airdromes, and they recognized the importance of placing them in proximity to critical resources—which is reflected in the TLOM.26
These two formalized manuals, the Small Wars Manual and the TLOM, show the large influence of the campaign in Nicaragua on formalizing aviation doctrine. Not only would these doctrines be implemented later in the Pacific, but many of the officers who fought and flew in Nicaragua also would serve during World War II.
The campaign in Nicaragua was exactly what Marine Corps aviation needed to experiment, innovate, and develop methods to carry out air warfare. Aviation was an untested technology before, and its role in warfare was not fully understood. Although the Marine Corps had aviators during World War I, the aviators did not have the chance to “join the fray as part of a Marine Corps team.”27 As a result, aviation doctrine and strategy were underdeveloped, and few officers had combat experience. This meant that Nicaragua was the first opportunity for the Marines to firmly establish the role of aviation in warfare.
From Tech Innovation to Tactical Innovation
Today, the United States faces a similar situation. There are many technologies, including drones, unmanned surface vessels (USVs), and cyber weapons, that have been developed but not rigorously deployed in combat yet. This means there is no firm doctrine or understanding as to how these technologies might be applied or possibly change the face of warfare. However, the conflict in Ukraine with Russia, a near-peer adversary of the United States, has shown just how important it is to test out new technologies in combat.
Despite the fact that the technology for unmanned aerial vehicles (UAVs) has been developing for decades, the United States has used UAVs only in a narrow and limited manner. Furthermore, it has used them primarily to track and kill high-value targets in the fight against terrorism.
When the conflict in Ukraine started in February 2022, many assumed drones would continue to be used the same way the United States had used them in the Middle East. To the surprise of many, Ukraine developed completely new ways of using drones against Russia. For example, Ukraine used cheaper, smaller drones compared with the larger U.S. models. These smaller models, costing only around $500, were outfitted with smaller ordnance and sent into Russian troop concentrations or vehicles. Although some drones were destroyed before reaching their targets, the large quantity of deployable drones made them a formidable weapon.
Moreover, the drones were far more cost- and material-effective, since they were significantly more precise than standard artillery is. As a result, most drone strikes sent by Ukraine resulted in significant casualties among Russian personnel, showing the adaptability of drones in a way not previously considered.28 In addition to drones, Ukraine has fielded USVs into the Black Sea, causing significant damage to Russian naval vessels.
The United States also has been developing USVs.29 The idea is to have a small, cheap, and highly maneuverable craft that can be sent into hostile waters to attack enemy vessels. Ukraine took this idea and adjusted the USVs to conduct strike warfare. After outfitting each unmanned vessel with a warhead that detonated on impact, Ukraine sent them into the Black Sea to attack Russian ships.30 So far, Ukraine has launched at least two successful attacks, sending numerous USVs at once toward a Russian vessel and hitting the warships Kunikov and Ivanovets.31
Ukraine’s examples of innovation in drone usage both by air and by sea show how testing out technology in warfare is one of the best ways to prepare for war, evolving the new technology’s role and strategic possibilities through the testing ground of combat. Ukraine’s innovative uses of UAVs and USVs have completely changed the way they are employed.
Fertile Ground for Great Strides Forward
The story of aviation in the Second Nicaraguan Campaign is the story of a young adolescent maturing into adulthood. Prior to conflict in Nicaragua, aviation had been used by the Marine Corps, but never to a large extent. Aviation was seen as a potentially useful tool, but the Marine Corps did not understand how it could be used effectively in war. The Second Nicaraguan Campaign was fertile ground for new technology and doctrines, which sprouted in the pages of The Marine Corps Gazette and bloomed with the publication of the Small Wars Manual and the Tentative Landing Operations Manual.
Throughout the conflict, Marine aviators made important improvements to the tactics and doctrine, including dive-bombing, air-ground communications, and the introduction of transport planes. Moreover, the experience gained by the aviator officer corps formed the backbone of Marine aviation leadership during World War II.
Today, as the United States faces potential conflict with a near-peer adversary, it should look to Marine Corps aviation during the Second Nicaraguan Campaign as a shining example of a novel technology turning into a powerful weapon of war. Despite having many new technologies, the United States has tested few in combat. If it seeks success against a near-peer adversary, its new technologies must be used in the battlespace to develop comprehensive doctrine and gain experience. This will turn these new technologies into potent weapons, giving the United States a decisive advantage in combat.
1. This was the second time U.S. Marines were sent into Nicaragua in the 20th century. From 1910 to 1912, U.S. Marines were sent to Nicaragua to protect U.S. property amid an earlier civil war. Hence, the Second Nicaraguan Campaign. Lester D. Langley and Thomas Schoonover, The Banana Men: American Mercenaries & Entrepreneurs in Central America, 1880–1930 (Lexington, KY: University Press of Kentucky, 1995), 91–94.
2. Henry Stimson was sent to Nicaragua on 31 March 1927. By 11 May, the Tipitapa agreement had been formalized and agreed to by both General José Maria Moncada, who represented the Liberals, and President Adolfo Diaz, who represented the Conservatives. Henry Stimson, American Policy in Nicaragua: The Lasting Legacy (New York: Markus Wiener, 1927), 34.
3. Stimson, American Policy in Nicaragua, 37.
4. Maj Edwin H. Brainard, USMC, “Marine Corps Aviation,” The Marine Corps Gazette 13, no. 1 (March 1928): 34–35.
5. Capt Francis E. Pierce, USMC, “Infantry-Air Communication,” The Marine Corps Gazette 13, no. 4 (December 1928): 268–69.
6. Wray R. Johnson, Biplanes at War: U.S. Marine Corps Aviation in the Small Wars Era, 1915–1934 (Lexington, KY: University Press of Kentucky, 2019), 211.
7. Pierce, “Infantry-Air Communication,” 268.
8. Maj Edwin H. Brainard, USMC, “The Marines Take Wings,” The Leatherneck, August 1928, 29.
9. Brainard, “The Marines Take Wings,” 29.
10. Maj Ross E. Rowell, USMC, “Annual Report of Aircraft Squadrons, 2nd Brigade,” The Marine Corps Gazette 13, no. 4 (December 1928): 254–55.
11. Rowell, “Annual Report,” 252.
12. Lt C. F. Schilt, in January 1928, made ten round trips in one day between Quilali, where the Marines were injured, and the Marine garrison in Ocotal. Brainard, “The Marines Take Wings,” 33.
13. Rowell, “Annual Report,” 252.
14. Maj Ross E. Rowell, USMC, “Aircraft in Bush Warfare,” The Marine Corps Gazette 14, no. 3 (September 1929): 187.
15. Maj Gary L. Thomas, USMC, “United States Marine Corps Air-Ground Integration in the Pacific Theater,” Air Command and Staff College Wright Flyer Paper no. 9 (November 1999): 2.
16. Johnson, Biplanes at War, 213.
17. Johnson, 213.
18. Rowell, “Aircraft in Bush Warfare,” 182–88.
19. Capt H. Denny Campbell, USMC, “Aviation in Guerrilla Warfare,” The Marine Corps Gazette 16, no. 3 (November 1931): 33–40.
20. Department of the Navy, “Aviation,” in Small Wars Manual (Washington, DC: Government Printing Office, 1940), 21.
21. Department of the Navy, “Aviation,” 20.
22. Maj Matthew T. Ritchie, USMC, The Influence of Marine Aviation on the Development of the Tentative Landing Operations Manual (Fort Leavenworth, KS: U.S. Army Command and General Staff College, 2013), 2.
23. Department of the Navy, Landing Operations Doctrine (Washington, DC: Government Printing Office, 1938), 159.
24. Rowell, “Aircraft in Bush Warfare,” 194–95.
25. Rowell, 184.
26. Department of the Navy, Landing Operations Doctrine, 158.
27. Capt Charles W. Boggs Jr., USMC, “Marine Aviation: Origins and Growth,” The Marine Corps Gazette 34, no. 11 (November 1950): 71.
28. Mariano Zafra et al., “How Drone Combat in Ukraine Is Changing Warfare,” Reuters, 26 March 2024.
29. Mallory Shelbourne and Sam Lagrone, “Navy Will Stand Up Lethal Drone Unit Later This Year, First Replicator USVs Picked,” USNI News, 14 February 2024.
30. H. I. Sutton, “USVs at Work in the Black Sea,” U.S. Naval Institute Proceedings 148, no. 12 (December 2022): 10–11.
31. Hasan Özyurt, “Analysis: An Operational View on the USV Attacks in the Black Sea from an Admiral’s Eyes,” Naval News, 18 February 2024.
