The staff spent much of its time in the 1920s and 1930s planning for manpower and industrial mobilization, planning which proved of great value in 1940 and 1941. The National Defense Act of 1920, an amendment to the 1916 act, rejected general staff requests for a 500,000 man army and universal military training. The expedition and further disorders along title border severely taxed the army. Woodrow Wilson called the National Guard to federal service in June 1916 to reinforce the army along the border. The mobilization went badly and raised further doubts within the army general staff about the value of the guard. From the branch schools for infantry and artillery, to the Army Air Corps Tactical School, to the Command and General Staff College, to the Army War College, captains, majors, and lieutenant-colonels served as students and instructors.