In December 2006, the US Army and Marine Corps published their new counterinsurgency doctrine manual to much fanfare. Field Manual (FM) 3-24 Counterinsurgency (Marine Corps Warfighting Publication 3-33.5) was well received by a military that has called for an updated counterinsurgency doctrine since at least 2003. FM 3-24’s writing team used counterinsurgency literature from European anti-colonial struggles to form FM 3-24’s foundation. Surprisingly, the FM 3-24 team chose to not utilize the vast numbers of US experiences in counterinsurgency, which date back well over 100 years. One of these discounted experiences was the US Army’s counterinsurgency campaign in the Philippines in 1899-1902, which is regarded by many as one of the US Army’s most successful counterinsurgency campaigns.
The key tactical lessons learned during the Philippines experience are as relevant today as they were in 1902. These lessons learned are the importance of small-unit leadership; the need for small-unit operations and mobility; the importance of local troops; the need for an effective intelligence apparatus; and the significance of degrading the insurgent shadow government infrastructure. The Army, however, failed to place these lessons into doctrine after 1902 because of its long tradition of relegating insurgent warfare to the fringes of military art and science. This decision ensured that Army officers and soldiers were not exposed to the Philippine lessons learned and that these experiences were eventually forgotten. This trend, unfortunately, continues to the present day as FM 3-24 excludes the numerous insights gathered from a close examination of the Philippine campaign, thus preventing them from being part of Army counterinsurgency doctrine.
On 10 December 1898, Spain signed the Treaty of Paris, which ended the Spanish-American War and ceded the Philippines, Cuba, Puerto Rico, and Guam to the United States. The US had been active in the Philippines since Commodore George Dewey defeated the Spanish fleet at the Battle of Manila Bay in May 1898. Philippine rebels under the leadership of Emilio Aguinaldo declared independence on 12 June and began attacking Spanish forces throughout the archipelago. US forces arrived to besiege Manila and tensions immediately increased between the US forces and Aguinaldo’s forces. The Spanish in Manila made an agreement with US forces to surrender the city after providing only token resistance to reaffirm Spanish honor. US forces subsequently attacked Manila on 13 August and took the city without Filipino help, although the Filipinos did seize some of Manilla’s suburbs. Aguinaldo’s men returned to their trenches and began their own “peaceful” siege of the city, except this time the Americans were the ones in Manila being besieged. 
Tensions continued into the fall as both the US Army and Filipino forces worked to avoid a conflict. The McKinley administration increasingly leaned toward making the Philippines a colony, despite a strong anti-imperialist movement in the US. Aguinaldo and his supporters hoped those Americans opposed to colonizing the Philippines would win out. Both sides did not want to make a move until negotiations between Spain and the US in Paris were concluded. On 10 December 1898, the Spanish-American War was concluded when Madrid and Washington agreed to the Treaty of Paris, which gave the Philippines to the US in exchange for $20 million. McKinley subsequently notified the secretary of war on 21 December that he wanted to administer the Philippines.
Hostilities broke out on 4 February 1899; the US Army defeated the Filipino forces in a number of running engagements. By mid-November 1899, Aguinaldo sought refuge in the hills and called on his forces to turn from conventional to guerrilla warfare. According to Brian Linn, his strategy was to protract the conflict until the US Army “broke down from disease and exhaustion or the American public demanded a withdrawal.” The Filipinos hoped the anti-imperialist candidate, William Jennings Bryan, would win the 1900 presidential election and demand a US withdrawal from the Philippines. They were to be let down yet again.
The Filipino forces were better able to fight an insurgency than a conventional fight. They had experience fighting this kind of conflict against the Spanish in 1896-1897. The geography was in their favor too: the Philippines was composed of 7,000 islands (with a population of over seven million). The insurgents were from the areas they were fighting in, spoke the language, understood the culture, and knew the terrain. There were groups of full time partisans who operated in the countryside while a part-time militia remained in the towns. The Republican government also established municipal and provincial governments and these later served as the insurgent underground government infrastructure. These shadow elements collected taxes, supervised the organization of supplies, gathered intelligence about the US Army, hid guerillas, and intimidated those that worked with the Americans.
By December 1899, the Americans under General Otis controlled the majority of the Philippines, had overwhelmed the Republican army, and were pursuing Aguinaldo and the remnants of his leadership. Otis was convinced the war was, for the most part, over. As occurred in Iraq in 2003, however, the Americans failed to understand that the war had transitioned from a conventional phase to an insurgency.
One of the key reasons for success in any counterinsurgency effort is small-unit leadership. This was certainly the case for the US Army in the Philippines. US Army junior officers were in charge of small garrisons in isolated districts where they were expected to pacify the area, create local government, and engage in infrastructure development. US army posts in the Philippines increased from several dozen by the end of 1899 to 639 two years later. The junior officers leading these posts quickly realized that Otis was incorrect in believing the war was over and that civic pacification programs would be enough to garner Filipino support. They struggled, initially, to build municipal governments, as many of the townspeople were either supporting the guerrillas or were afraid the guerrillas. Despite the initial frustrations, stumbles, and failures, the junior officers adapted to the environment and began developing counterinsurgency efforts tailored to succeed in their areas. Those that did not were eventually replaced.
The successful officers engaged in many activities to defeat the insurgents. They collected intelligence; hired Filipino auxiliaries to assist them even when Manila did not support this policy; used policies such as crop burning, food rationing, and concentration to isolate the population from the insurgents; and developed ways to reward Filipinos who supported US efforts, while penalizing those that did not. The US Army had no counterinsurgency doctrine and leaders at the tactical level, at least in the beginning of the guerrilla fight, received inadequate guidance from the generals running the war in Manila. Andrew Birtle believes one of the key reasons for US success in the Philippines was how US Army junior officers’ were willing to use trial and error to learn how to conduct counterinsurgency. The junior officers were the tip of the spear in the fight. Without their adaptability and initiative, the US Army would have been hard pressed to succeed in Philippines.
Similar to the Philippines campaign, small unit leadership remains a core of counterinsurgency efforts in the present day. Chapter Seven of FM 3-24 focuses exclusively on “Leadership and Ethics for Counterinsurgency.” Paragraph 7-15 says, “Success in COIN operations requires small-unit leaders agile enough to transition among many types of missions and able to adapt to change…alert junior leaders recognize the dynamic context of a tactical situation and can apply informed judgment to achieve the commander’s intent in a stressful and ambiguous environment.” Additionally, Paragraph 1-157 of FM 3-24 says, “Many important decisions are not made by generals.” Small unit leadership was essential in helping turn the tide in Iraq and it has played a critical role in the current effort in Afghanistan.
A second reason for US improvements in the Philippines was the army’s use of small-unit operations and mobility. Army leaders at the tactical level realized early on that large-scale operations against the insurgents would not be enough. The rebels were too fast and possessed a better understanding of the terrain. Many American commands began to operate in small units at night, laying ambushes, and launching efforts to surround and surprise an insurgent camp at dawn. US forces also sought to be more mobile. They jettisoned heavy packs and created mule trains and hired indigenous means of transport such as native workers or water buffalos. Garrisons also formed elite mounted units, which served as a quick relief force, but also conducted offensive actions against guerrilla camps and supplies.
US forces also used Filipino auxiliaries as mobility troops, and these forces served as a long range reconnaissance or strike force that sought out insurgent camps. General Arthur MacArthur, who replaced General Otis as Commander in the Philippines, also redistributed his forces by pulling troops from peaceful areas to utilize them as “flying columns” that would go after insurgents in more dangerous areas. Small unit operations and improved mobility helped US forces eventually capture or force the surrender of many insurgent leaders and their soldiers.
Although small unit operations do not have a specific chapter in FM 3-24, the manual does place great importance on the topic. FM 3-24 states, “Squads and platoons execute mostly COIN operations. Small-unit actions in a COIN environment often have more impact than similar actions during major combat operations.” The manual also talks about the need for denying sanctuary to the insurgents and for conducting offensive operations. US Special Forces and regular units in Iraq and Afghanistan have undermined enemy forces by targeting insurgent leaders, protecting the population at the local level, and gathering intelligence. Mobility was important in reducing the insurgent threat in Baghdad, and it is essential in remote Afghanistan. Small-unit operations and mobility were key to the US success in the Philippines, and they continue to be at the core of any successful counterinsurgency effort in the 21st Century.
A third reason why the US Army succeeded in the Philippines was because it employed native forces against the insurgents. Auxiliary troops are needed because they better understand the culture, language, local dynamics, and terrain. Local troops can also help the foreign counterinsurgent by serving as a bridge to the population. In 1899, some Indian War veterans realized the “divide and conquer” strategy of the American West would be needed in the Philippines. They also realized how demoralized the insurgents would be once they realized their own people were opposing them. Some senior US Army leaders did not support such ideas. They were concerned about local troops’ reliability and whether they would help the insurgents as spies and as an insider threat. There was also concern about local troops committing atrocities that could undermine the pacification campaign.
This apprehension frustrated many leaders at the tactical and district level. They knew they needed local police and troops to defeat the insurgents. Some officers chose to ignore Manila’s concerns about local troops and developed informal units of auxiliaries and volunteers, such as the Ilocano Scouts and Bicol Volunteers in Southern Luzon. MacArthur initially followed Otis’s cautious policy regarding local troops, but he reversed this course in December 1900. The US victory in the 1899-1902 Philippine counterinsurgency campaign would not have been possible without their support.
The importance of local troops in a counterinsurgency effort continues to this day. US forces in both Iraq and Afghanistan quickly realized the need for local support because Americans did not understand the language or the culture. FM 3-24 emphasizes the importance of this with an entire chapter devoted to local troops. Chapter Six, “Developing Host-Nation Security Forces,” discusses the challenges and the need for adequate local military support. Paragraph 6-107 says, “Developing effective host nation security forces is one of the highest priority counterinsurgency tasks.” It is essential to have local auxiliaries or security forces support in an effort to divide the insurgency’s base of support.
A fourth reason the US Army succeeded in the Philippines was because it developed an effective intelligence apparatus. Many American commanders were unaware during the pacification effort that the insurgents had a shadow government and infrastructure in the towns. The shadow government ran a parallel administration, collected taxes, and intimidated those Filipinos that might work with the Americans. The insurgent infrastructure also supplied the insurgents with food and intelligence about American policies and troop movements. An American colonel said the US Army was like “a blind giant.” He further added, “The troops were more than able to annihilate anything that could be brought against them…but it was impossible to get any information in regard to the insurgents.”
Progress toward getting better intelligence began with a junior officer in northern Luzon in spring 1900. Lt. William Johnston allied himself with a Filipino faction opposed to the insurgents and they began educating him on how the rebels operated. He wrote a paper called “Investigation into the Methods Adopted by the Insurgents for Organizing and Maintaining a Guerrilla Force.” Johnston utilized Human Intelligence to accurately expose the provincial insurgent organization. He demonstrated how the insurgents in the field were tied to the shadow governments and part-time militias in the towns. Johnston claimed his report was “the first news that the insurrectos were actively at work organizing and the first indication that the American authorities had that the native officials of the town and others were playing a double role.” MacArthur called it “altogether the best description which has reached these headquarters of the insurgent method of organizing and maintaining a guerrilla force.”
Johnston’s report helped US forces better comprehend the threat. Birtle highlights how the US Army began to realize it needed to devote more attention to intelligence gathering. It developed source networks to gather information, created a special agency to translate captured documents, and developed intelligence files on insurgent leaders. These improvements in intelligence greatly assisted US efforts to dismantle the insurgents’ underground infrastructure. Intelligence is a key aspect of any counterinsurgency effort. It is difficult to defeat an insurgency without understanding how it fights, how it is supplied, and who its supporters are. US forces did not understand this in 1899, but once they did, they were able to develop a good intelligence infrastructure that was critical in helping defeat the insurgency by 1902.
Intelligence continues to be a critical component of counterinsurgency efforts. FM 3-24 says “Intelligence drives operations.” It also states that, “Without good intelligence, counterinsurgents are like blind boxers wasting energy flailing at unseen opponents…with good intelligence, counterinsurgents are like surgeons cutting out cancerous tissue while keeping other vital organs intact.” Chapter Three of FM 3-24 is called “Intelligence in Counterinsurgency” and has 35 pages devoted to intelligence in a counterinsurgency effort. Intelligence was a key component in the US defeat of Filipino insurgents in 1902, and it will always be a key part of any counterinsurgency effort.
Success in the Philippines could not occur unless the US Army was able to dismantle the insurgents’ shadow government infrastructure. The insurgents needed the people’s support or, at a minimum, their compliance. They used their underground system to achieve this support through appeals to patriotism or by coercion. The US Army struggled in its initial pacification effort because the insurgent underground government was well established. The Army also did not realize the towns were the primary insurgent bases for supplies and that the shadow systems were the real authorities in the towns. The Filipino people were not going to support American efforts unless the US Army demonstrated that it could protect its friends and punish its enemies.
Some commanders realized they had to go after the insurgents’ underground infrastructure, and MacArthur’s December 1900 declaration gave official sanction to do this. He realized the rebels’ ultimate survival rested on their ability to control the civilian population. US forces developed intelligence networks and began to identify insurgent supporters. Once they were identified, US and Filipino auxiliaries used positive incentives (the carrot) or negative consequences (the stick) to dismantle the shadow governments. If someone supported the rebels, that person could lose his crops, land, and ultimately be jailed. If they supported the US, they could keep all of their holdings, engage in trade, and hold public office.
As the war continued, many Filipinos realized accommodation with the US was safer and more profitable. As a result, insurgent commanders turned to more coercive methods to retain support and these ultimately failed and alienated the population. A “bandwagon effect” occurred as more Filipinos sided with the US Army because they realized the insurgents were going to lose the fight. Insurgent morale plummeted and many commanders and fighters began to surrender. Without the underground infrastructure, the fighters in the field could not continue.
The targeting of insurgent shadow governments and their corresponding infrastructure is a key component of FM 3-24. Paragraphs 1-128 to 1-130 discuss how insurgents must be isolated from their cause and support: “It is easier to separate an insurgency from its resources and let it die than to kill every insurgent…Eventually, the people marginalize and stigmatize insurgents to the point that the insurgency’s claim to legitimacy is destroyed.” This occurred when one of the most famous insurgents, Major General Miguel Malvar, surrendered. He said he did because of, “reconcentration, the complete cleaning up of food supplies outside the towns, persecution of the insurgent soldiers by the people, the search for myself by the people, and the demoralization of my troops.” The destruction of Malvar’s infrastructure resulted in a loss of support and led to his eventual surrender.
On 4 July 1902, President Theodore Roosevelt declared an end to the Philippines conflict. As in all successful counterinsurgencies, there was no one single reason for the US Army’s success. All of the previously mentioned key lessons learned were significant in their own right, but they had to be combined to ensure success. The US Army’s ignorance of the threat at the end of the conventional war doomed it to a longer conflict. The initial benevolent pacification policy had some success, but it alone could not defeat the insurgents. The insurgent shadow government infrastructure’s influence over the Filipino population had to be reduced if the US Army was to succeed.
The Army learned through trial and error that the carrot alone was not going to be enough to defeat the insurgents. The Philippines campaign demonstrated there is no magical formula for conducting a counterinsurgency. It did, however, show the need for a mixed stick/carrot approach while highlighting that military solutions cannot be relegated to secondary measures. The insurgent shadow infrastructure must be uprooted and its influence over the population diminished before carrot approaches can make a significant impact.
Despite learning these important lessons, the Army did not create any doctrine or lessons learned in writing that could have helped future Army officers. As Brian Linn points out, “most veterans of the imperial conflicts devoted little attention to retrospective analysis. Nor did the army make much effort to incorporate the lessons of its Philippine experience into training or professional education.” US Army Major General Leonard Wood echoed these sentiments when he said the lessons learned in such conflicts were “of little value and usually result in false deductions and a confidence, which spells disaster when called upon to play the real game.” Students at Fort Leavenworth and the Army War College in the pre-WW I period studied conventional conflicts such as the American Civil War, German wars of unification, and the 1905 Russo-Japanese War.
Linn opines that the reason why so many in the Army ignored insurgent warfare was because Army leaders believed such conflicts taught the wrong lessons. These leaders were concerned that too many officers had developed individual initiative and small unit leadership skills in insurgent conflicts. According to Linn, they believed these skills were not helpful to the “discipline and doctrinal adherence required by large-unit operations.” Birtle offers a slightly different perspective. He cites three reasons for why the Army did not incorporate Philippine lessons learned into doctrine. First, the Army believed the Philippines fighting validated prewar small-unit tactical doctrine and that only small adjustments needed to be made. Second, the Army’s successful efforts reaffirmed the belief that guerrilla warfare was not capable of bringing about victory. Birtle’s last reason may be the most important: the Philippines fighting was unpopular in the US and the Army was reluctant to record official lessons learned that could have led to more public scrutiny of the conflict.
The Army’s lack of attention regarding insurgencies continued into the post-WW I era. US Army officers studied conventional conflicts and paid only minor attention to counterinsurgency efforts, even though the majority of the Army’s history had been spent fighting insurgencies. When Army officers examined insurgencies, they studied European colonial struggles. Lessons learned from the Philippines campaign were largely forgotten or relegated to the fringe of military science. During the Cold War era the US Army concentrated on conventional fighting, with the Soviet threat being the focus. The Vietnam conflict, however, forced the army to reexamine counterinsurgency, and some US officers likely studied the Philippines conflict. Any lessons learned, however, were mostly overlooked, as the Army, in Linn’s estimation, transitioned back to concentrating on conventional threats in the post-Vietnam era.
Following the 9/11 attacks, the Army found itself embroiled in fighting insurgencies in Iraq and Afghanistan. To counter these efforts, the Army and the Marine Corps reexamined their counterinsurgency doctrine and published FM 3-24. Despite the Philippines campaign’s success, however, FM 3-24’s writers chose to exclude it, even though many of the tenets discussed in FM 3-24 were learned in the Philippines.
This is illustrated by comments made by Dr. Conrad Crane, the Director of the US Army Military History Institute, who was the lead author for FM 3-24. He wrote, “When the Army–Marine Corps writing team for Field Manual (FM) 3-24 began their deliberations, they turned to these sages (David Galula, Frank Kitson, Robert Thompson, and Roger Trinquier) of the past to develop a baseline list of principles upon which to build the new doctrinal manual.” Dr Crane’s comment is reinforced by Dr. John Nagl, another writer on the FM 3-24 team, who said, “It is true that the manual draws heavily from the ‘classical’ counterinsurgency theorists such as David Galula and Sir Robert Thompson and their experiences combating Maoist insurgencies and anti-colonial conflicts that marked the first two decades of the Cold War.” US experiences and lessons learned, such as those from the Philippines campaign, were not used for the most part. Indeed, there is only one mention of the Philippines campaign in FM 3-24. It can be found in Paragraph 1-16 and it says, “The United States began that century [20th Century] by defeating the Philippine Insurrection.” The Source Notes section does not include any references to materials on this campaign, although the Annotated Bibliography does mention Linn’s book The Philippine War, 1899-1902, and calls it “the definitive treatment of successful US counterinsurgency operations in the Philippines.” Birtle’s impressive book on US Army counterinsurgency experiences from 1860-1941 is not mentioned anywhere in FM 3-24. This seems a significant oversight as the US military has learned all the counterinsurgency lessons found in FM 3-24, and then some, in American-led campaigns. Birtle’s comprehensive effort captures US Army counterinsurgency lessons learned spanning an 81-year period from the American Civil War to WW I.
Despite the Army’s success, the Philippines campaign of 1899-1902 remains one of the least known counterinsurgency efforts in the US Army today. The key tactical lessons learned during the conflict remain as relevant in today’s fights as they were in 1902: the importance of small-unit leadership; the need for small-unit operations and mobility; the importance for local troops; the need for an effective intelligence apparatus; and the significance of degrading the insurgent shadow government infrastructure. Each of these aspects can be found in FM 3-24 in some capacity, and remain core components of the military’s counterinsurgency doctrine. Unfortunately, the Philippine lessons learned were never codified into any type of doctrine and this is one of the reasons why these lessons were forgotten. The Army has an unfortunate tradition of considering insurgent conflict a sideshow effort and relegating the study of insurgencies to the fringes of military science. The Philippines campaign is a prime example.
Disclaimer: The views expressed in this article are those of the author alone and do not reflect the official policy or position of the US Army Reserve, the Department of Defense, or the US Government.
 David J. Silbey, A War of Frontier and Empire (New York, 2007) 58. Brian McAllister Linn, The U.S. Army and Counterinsurgency in the Philippine War, 1899-1902 (Chapel Hill, 1989) 1. Brian McAllister Linn, The U.S. Army and Counterinsurgency in the Philippine War, 1899-1902 (Chapel Hill, 1989) 1.
 Linn, The U.S. Army and Counterinsurgency in the Philippine War, 9. Silbey, A War of Frontier and Empire, 121.
 Andrew J. Birtle, U.S. Army Counterinsurgency and Contigency Operations Doctrine 1860-1941 (Washington, D.C., 1998) 112. Brian McAllister Linn, The Philippine War 1899-1902 (Lawrence, 2000), 42. Silbey, A War of Frontier and Empire, 121.
 Linn, The U.S. Army and Counterinsurgency in the Philippine War, 17. Silbey, A War of Frontier and Empire,
 Linn, The Philippine War 1899-1902, 180-181. Linn, The U.S. Army and Counterinsurgency in the Philippine War, 21.
 Silbey, A War of Frontier and Empire, 145. Birtle, U.S. Army Counterinsurgency and Contigency Operations Doctrine 1860-1941, 111-113, 124-127.
 Birtle, U.S. Army Counterinsurgency and Contigency Operations Doctrine 1860-1941, 112-119. Linn, The Philippine War 1899-1902, 206.
 Department of the Army. FM 3-24, Counterinsurgency (Washington, D.C.: Government Printing Office, December 2006), 7-1, 7-3.
 Birtle, U.S. Army Counterinsurgency and Contigency Operations Doctrine 1860-1941, 114. Linn, The Philippine War 1899-1902, 222.
 Linn, The Philippine War 1899-1902, 216. Silbey, A War of Frontier and Empire, 156.
 Department of the Army, FM 3-24, Counterinsurgency, A-3
 Birtle, U.S. Army Counterinsurgency and Contigency Operations Doctrine 1860-1941, 116.
 Linn, The Philippine War 1899-1902, 204. Linn, The U.S. Army and Counterinsurgency in the Philippine War, 169
 Department of the Army, FM 3-24, Counterinsurgency, 6-1, 6-22
 Linn, The Philippine War 1899-1902, 191. Birtle, U.S. Army Counterinsurgency and Contigency Operations Doctrine 1860-1941, 111-112. Silbey, A War of Frontier and Empire, 148.
 Linn, The U.S. Army and Counterinsurgency in the Philippine War, 42.
 Linn, The U.S. Army and Counterinsurgency in the Philippine War, 42-44
 Birtle, U.S. Army Counterinsurgency and Contigency Operations Doctrine 1860-1941, 117.
 Department of the Army, FM 3-24, Counterinsurgency, 1-23, 3-1
 Ibid., 191.
 Birtle, U.S. Army Counterinsurgency and Contigency Operations Doctrine 1860-1941, 125.
 Birtle, U.S. Army Counterinsurgency and Contigency Operations Doctrine 1860-1941, 128, Linn, The U.S. Army and Counterinsurgency in the Philippine War, 18, 26. Silbey, A War of Frontier and Empire, 208.
 Linn, The Philippine War 1899-1902, 192. Birtle, U.S. Army Counterinsurgency and Contigency Operations Doctrine 1860-1941, 132
 Department of the Army, FM 3-24, Counterinsurgency, 1-23. Linn, The U.S. Army and Counterinsurgency in the Philippine War, 159.
 Silbey, A War of Frontier and Empire, 205.
 Brian McAllister Linn, The Echo of Battle: The Army’s Way of War (Boston, 2009) 86-87, 89
 Brian McAllister Linn, The Echo of Battle: The Army’s Way of War (Boston, 2009) 86-87. Birtle, U.S. Army Counterinsurgency and Contigency Operations Doctrine 1860-1941, 138.
 Linn, The Echo of Battle: The Army’s Way of War, 90, 179-182, 193-194.
 Conrad C. Crane, “Minting COIN,” Air & Space Power Journal-Winter 2007, found at http://www.airpower.maxwell.af.mil/airchronicles/apj/apj07/win07/crane.html . John A. Nagl, Constructing the Legacy of Field Manual 3-24, Joint Forces Quarterly, Issue 58, Third Quarter 2010, found at http://www.ndu.edu/press/constructing-3-24.html.
 Department of the Army, FM 3-24, Counterinsurgency, 1-3, Annotated Bibliography-2