How and why the 1917 Russian revolution degenerated into the totalitarian and bureaucratic nightmare of Stalinism

USSR
The Iranian revolution – a Marxist perspective
1979 saw the overthrow of the Shah of Iran and the coming to power of Ayatollah Khomeini – an event that split the Left inside the country
1979 Iran revolution – a Marxist perspective
The Iran revolution in 1979 was taken over by Ayatollah Khomeini and the mullahs which most on the Left saw as a reactionary development