On February 19, 1898, the battleship USS Maine suffered a massive explosion in Havana Harbor that was quickly blamed on Spanish forces that occupied Cuba. In April 1898, Spain declared war on the United States and the United States declared war on Spain resulting in the start of the Spanish American War. Conflict between Spanish and American forces occurred in Cuba, Puerto Rico, Philippines and Guam. President McKinley called for 50,000 men to join the Army and received over 220,000 including volunteers from the State Militia and National Guard units.
Washington National Guard was mobilized for service, but the war ended in August 1898 before the Washington Volunteers were sent overseas. However, the United States declared its intent to control the Philippines which was contrary to the Filipino desire for independence thus resulting in the start of the Philippine Insurrection or Philippine-American War. A regiment of Washington Volunteers was sent to the Philippines arriving in November 1898. The Washington boys participated in several battles around Manila before returning home October 1899 to a ticker tape parade in Seattle.