The National Guard

The National Guard traces its origins to colonial militias, and it marks its birthday as December 13, 1636, when Massachusetts Bay organized its first regiments. The Constitution gives Congress power to call forth the militia to execute the laws, suppress insurrections, and repel invasions, and to organize, arm, and discipline it, while reserving to the states the appointment of officers and training. The Militia Act of 1903 and the National Defense Act of 1916 turned state militias into the modern National Guard, organized and equipped like the regular Army, and the Air National Guard was created in 1947.

Every state, the District of Columbia, Puerto Rico, Guam, and the U.S. Virgin Islands has a Guard, with more than 400,000 members combined. Guard members can serve in three statuses: state active duty, under the governor's command and paid by the state, for disasters and civil unrest, Title 32 status, under the governor's command but federally funded, and Title 10 federal service, under the President's command. In federal service, Guard units have fought in every major war and deployed heavily to Iraq and Afghanistan. The National Guard Bureau in the Pentagon coordinates the Guard, and its chief has sat on the Joint Chiefs of Staff since 2012.

Presidents have federalized the Guard over governors' objections to enforce federal law, including in Little Rock in 1957 and Alabama in 1963 and 1965. In Perpich v. Department of Defense in 1990, the Supreme Court held that governors cannot block federal training missions abroad. In 2025 the President federalized California Guard troops over the governor's objection to protect federal immigration operations in Los Angeles, deployed Guard troops in the District of Columbia, and sought to send them to Portland and Chicago, prompting lawsuits over federal authority and the Posse Comitatus Act. Supporters cited the need to protect federal personnel, while critics said the deployments overrode state authority.