The Soviet Union has a single party system dominated by the Communist party. Although the USSR is nominally a union of Soviet Republics (of which there were 15 after 1956) with the capital in Moscow, it is in actuality a highly centralized state with a planned economy. Much of Soviet society is overseen by national security agencies such as the KGB (which has been active since 1954). The Soviet Union and its satellites from the Eastern Bloc were one of two participating factions in the Cold War and World War III.