Original sentence: A number of sources, including the FBI and Soviet archives, maintain that he engaged in espionage activity for the Soviet Union
Edited sentence: A number of sources, including the FBI, the Senate Internal Security Subcommittee, intercepted Soviet communications, and Soviet archives, maintain without reservation that he engaged in espionage activity for the Soviet Union, possibly making him the most highly-placed Soviet spy in the United States government.This directly lead to the weakening of the Nationalist government under Chiang Kai Shek and thus the Communist victory in the Chinese Civil War