What is the American Legion?  The American Legion is the largest wartime veteranâs service organization, with nearly 2 million members and more than 12,000 posts in communities throughout America. The America Legion was established by the act of Congress in 1919. The Legion was instrumental in getting the original GI Bill through Congress and the creation of the Department of Veterans Affairs. Today the American Legion is active throughout the United States, supporting current military personnel and veterans, sponsoring a variety of activities and events in local communities. The organization also pushes for the adoption of a constitutional amendment to prohibit desecration of the U.S. Flag.