What is the main conflict in The Manchurian Candidate by Richard Condon?

“The Manchurian Candidate” revolves around the life of Raymond Shaw, a veteran American sergeant who served in the Korean War. During the War, Shaw's unit was ambushed by Soviet agents, and the men were taken to a secret Soviet psychological research facility. Raymond was chosen to be trained as a sleeper assassin, due to his socially withdrawn demeanor, intense hatred toward his family, and excellent marksmanship. Programmed to obey any orders he hears after seeing the queen of diamonds during a game of solitaire, Raymond brutally kills two of the men in his unit at the research facility while the rest of his men watch. The rest of the unit, however, is also brainwashed into believing that Raymond single-handedly saved them during an enemy attack. When the men return home and relay this fake story, Raymond is awarded the prestigious Medal of Honor.