Chief of Staff on March 4 and was Army Chief of Staff on May 20, 1918. He was promoted to temporary general. Joseph M. Swing (a lieutenant general in World War II) was his new aide-de-camp. March was highly critical of President Wilson's decision to send an American Expedition to North Russia and Siberia in 1918 during the Russian Civil War (the so-called Siberian Intervention) ostensibly to prop-up the White movement war effort, secure the railroads, support the Czech Legion trapped there, and stop the Japanese from exploiting the chaos in order to colonize Siberia. March wrote after the pull-out of American forces in 1920: He served as chief of staff until June 30, 1921. As chief of staff he reorganized the Army structure, and abolished the distinctions between the Regular Army, the Army Reserves, and the National Guard during wartime. He created new technical branches in the service including the Air Service, Tank Corps, and Chemical Warfare Service. He also centralized control over supply. After the war ended, he supervised the demobilization of the Army. As chief of staff he often came into disagreement with General John J. Pershing, who wanted to conduct the AEF as an independent command. March was a highly efficient and capable administrator who did much to modernize the American Army and prepare it for combat in the First World War. Later life March retired as a major general in 1921 at the age of 56. In June 1930, March was advanced to general on the retired list as the result of a law which enabled World War I generals to retire at the highest rank they had held. After retirement, he travelled Europe, Africa and Turkey. In 1932, he published his war memoirs, The Nation at War. During World War II, reporters for Time and Life magazines regularly sought his opinions of events. He was a fan of the Washington Senators and regularly attended their home games. March died at the Walter Reed Army Medical Center on April 13, 1955, and was buried at Arlington National Cemetery. In his funeral marched "the escort commander and his staff; the United States Army Band; one battalion of cadets from the US Military Academy; one company of infantry; one battery of field artillery; one company of armor; the U.S. Marine Band; one company of Marines; one company of bluejackets; one squadron of airmen; and one composite company