Allen joined the army, lying about his age in order to do so, an exposé of the Hoover administration. After Hoover tracked down their identities, both authors were fired. In 1932 the two journalists published a sequel,
More Merry-Go-Round, According to John Earl Haynes, Harvey Klehr and Alexander Vassiliev in their 2009 book
Spies: The Rise and Fall of the KGB in America, this was legal for Allen to do, being prior to the passage of the 1938
Foreign Agents Registration Act, and his motivation is unknown. In 1937, during the
court-packing controversy, Allen and Pearson co-authored the book
The Nine Old Men, about the U.S. Supreme Court. During the early forties he co-wrote the newspaper strip
Hap Hopper with Drew Pearson. The strip was drawn by Jack Sparling. He served on
General Patton's staff in
World War II, reaching the rank of colonel. During a reconnaissance mission on April 7, 1945, near
Apfelstädt, close to
Erfurt, he got caught up in a firefight with a German unit and was seriously wounded. He was then taken prisoner and brought to a German military hospital in Erfurt. There, his arm was amputated. On April 11, 1945, he was liberated by soldiers of the 80th Infantry Division. His wartime diary was published after his death. In 1947, he edited the book
Our Fair City, an exposé of corrupt conditions in American municipalities. He also wrote ''Lucky Forward: The History of Patton's Third Army.'' Papers concerning his military career reside in the George S. Patton Museum at
Fort Knox, Kentucky. According to
documents released by the CIA in 2007, Allen was the subject of a wiretap operation,
Project Mockingbird.
Associated Press reported: "Under pressure from Attorney General Robert F. Kennedy" in 1962, CIA director John McCone "agreed to tap the telephones of columnists Robert S. Allen and
Paul Scott in an effort to identify their sources for classified information which was appearing in their columns," says a memo a decade later to the agency's director." ==Death==