Who was Rupert?
I respect Schindler for keeping secret the results of confidential investigations.
Never Trust a Checkist
Meticulous counterintelligence work, including rummaging through archives, reviewing yellowed case files, and interviewing the elderly, slowly revealed the identity of “Rupert.”
He was a prominent American who indeed did serve in U.S. Army intelligence in the Pacific during World War Two, achieving field-grade rank. And he was indoctrinated for a wide range of SIGINT secrets. U.S. intelligence files never hinted that he was a traitor, but he had been a hardline Communist before the war, though never an actual party member (often Soviet spies were told to steer clear of the Community Party, which was closely watched by the FBI).
After the war, however, “Rupert” had a change of heart and transformed into a Cold War liberal with anti-Communist views. His Bolshevism was a youthful indiscretion, and by the 1950s he was part of Washington, DC power circles and a friend to presidents, none of whom had any inkling of his secret past. .
OTOH, if "Rupert" was influential in DC in the 1950s, his dabbling in Communism and his brush with KGB spies is, potentially, an important part of history.