Communism
From Halopedia, the Halo wiki
Communism was a military, and cultural belief system on Earth in the 20th century, and it originated from the Soviet Union. Communism was ultimately dissolved during the 1990's in some nations of Earth.
The Neo-Communist hardliner, Vladimir Koslov, led a communist belief system called the Koslovics which fought against the UN during the Interplanetary War of 2160 - 2164.