Communist Party of the Soviet Union
The Communist Party of the Soviet Union (CPSU) was the ruling political party in the Soviet Union, and the only legal one.  The leaders of the party were Vladimir Ilyich Lenin, Joseph Stalin,  Lavrentiy Beria, Georgy Malenkov, Nikita Khrushchev, Leonid Brezhnev, Yuri Andropov, Konstantin Chernenko, and finally Mikhail Gorbachev.