Regiments from the guard first went overseas in the 1898 Spanish–American War, serving in the initial occupation of the Philippines. The Militia Act of 1903 organized the various state militias into the present National Guard system. In 1916 units were mobilized to patrol the Mexican border in response to aggressive actions by the Mexican Government, but no action occurred. The next year the entire guard was mobilized and many sent into action as part of World War I, most men being deployed to France.