A brief exerpt on The Spanish American War
The Filipino general Francisco Makabulos described the Filipinos' war aim as, "not to vanquish the US Army but to inflict on them constant losses." They sought to initially use conventional (later guerilla) tactics and an increasing toll of US casualties to contribute to McKinley's defeat in the 1900 presidential election. Their hope was that as President the avowedly anti-imperialist William Jennings Bryan would withdraw from the Philippines. They pursued this short-term goal with guerilla tactics better suited to a protracted struggle. While targeting McKinley motivated the revolutionaries in the short term, his victory demoralized them and convinced many undecided Filipinos that the United States would not depart precipitately
The guerrilla war phase
In 1900, Aguinaldo shifted from conventional to guerrilla warfare, a means of operation which better suited their disadvantaged situation and made American occupation of the Philippine archipelago all the more difficult over the next few years. In fact, during just the first four months of the guerrilla war, the Americans lost nearly 500 men who were either killed or wounded. The Philippine Army began staging bloody ambushes and raids. Most infamous were the guerrilla victories at Pulang Lupa and Balangiga. At first, it even seemed as if the Filipinos would fight the Americans to a stalemate and force them to withdraw. This was even considered by President McKinley at the beginning of the phase.
The shift to guerrilla warfare, however, only angered the Americans into acting more ruthlessly than before. They began taking no prisoners, burning whole villages, and routinely shooting surrendering Filipino soldiers. Much worse were the concentration camps that civilians were forced into, after being suspected of being guerrilla sympathizers. Thousands of civilians died in these camps. In nearly all cases, the civilians suffered much worse than the actual guerrillas.
The subsequent American repression towards the population tremendously reduced the materials, men, and morale of many Filipino soldiers, compelling them in one way or another to surrender.
American torture and scorched-earth campaigns
General Jacob H. Smith's infamous order, "Kill everyone over ten," was the caption in the New York Journal cartoon on May 5, 1902. The Old Glory draped an American shield on which a vulture replaced the bald eagle. Caption is: "Criminals because they were born ten years before we took the Philippines."In 1908, Manuel Arellano Remondo, in a book entitled General Geography of the Philippine Islands, wrote: "The population decreased due to the wars, in the five-year period from 1895 to 1900, since, at the start of the first insurrection, the population was estimated at 9,000,000, and at present (1908), the inhabitants of the Archipelago do not exceed 8,000,000 in number."[26]
U.S. attacks into the countryside often included scorched earth campaigns where entire villages were burned and destroyed, torture (water cure) and the concentration of civilians into "protected zones" (concentration camps). Many of the civilian casualties resulted from disease and famine. Reports of the execution of U.S. soldiers taken prisoner by the Filipinos led to savage reprisals by American forces. Many American officers and soldiers called war a "nigger killing business".
http://en.wikipedia.org/wiki/Philippine-American_War#War_Crimes