After the Cuban Missile Crisis, the Soviet Union planted a number of long-term, deep-cover sleeper agents all over the United States, spies so thoroughly Brainwashing that even they did not know they were agents and can be activated only by a special code phrase. (The phrase is a line from the Robert Frost poem "Stopping by Woods on a Snowy Evening", followed by the agent's real first name.) Their mission was to sabotage crucial parts of the civil and military infrastructure in the event of conflict.