Who maintained control of the Soviet Union by killing and Imprisoning his political enemies?

Soviet dictator Joseph Stalin.

Explanation:

Stalin maneuvered to take control of the party's central bureaucracy after the death of Vladimir Ilich Lenin in 1924. Then he managed to push aside other contenders for the top party job, including historical revolutionaries such as Leon Trotsky - who had to run away and went into exile - or Grigori Zinoviev, who was sent to trial in 1936 and executed. Stalin is also responsible for massive purges in the Red Army and in the Communist Party in the 1930s.