This is a list of feature films which can be useful in understanding different types of political systems in different parts of the world. (A few classics on nuclear war are included too.)
 

1900 (turn of century Europe)
1984 (George Orwell's vision of totalitarianism)
All the President's Men (US elections)
Amin (tyrant of Uganda)
Battle of Algiers (revolution in Algiers)[Gillo Pontecorvo]
Before the Rain (Bosnian civil war)
Beyond Rangoon (repression in Burma)
Black and White in Color (Colonialism in west Africa, World War I)
Burn (fictionalized slave trader in Caribbean)
Candidate (US elections)
Confession (purge trials in communist East Europe)[1970 Constantin Costa-Gavras]
Cry Freedom (South Africa)
Cry, Beloved Country (South Africa)
Darkness at Noon
Dr. Strangelove (nuclear nightmare) [Stanley Kubrick]
Dr. Zhivago (Russian Revolution)
El Salvador
Eleni (civil war in post World War II Greece)
Evita (Evita Peron of Argentina)
Executive Action (nuclear nightmare)
Failsafe (nuclear nightmare)
Full Metal Jacket ( Vietnam War horror film) [Stanley Kubrick]
Gandhi (anti colonial struggle in India)
Gorky Park (Soviet elite lifestyles)
Good Earth (peasant life in China, 1910-30)
Gulag (prison campus in the Soviet Union )
Great Dictator (Charlie Chaplin's great satire on Hitler)
Havana
Hearts and Minds (Vietnam war)
Hotel Rwanda
Killing Fields (genocide in Cambodia)
Mein Kampf
Missing (Pinochet's coup against Allende, Chile, 1972)[Constantin Costa-Gavras]
Olympia
Panama Deception
Paths to Glory (World War I horror of war) [Stanley Kubrick]
Power Play
Reds (Russian Revolution)
Rolling Thunder (Famine in India)
Ruling Class (satire of English aristocracy)
Sakharov (Soviet dissident)
Sands of Kalahari (primitive people in desert Africa)
Sand Pebbles (Chinese Revolution, 1930s)
Shoah (holocaust)
Spartacus (slave uprising, ancient Greece)[Stanley Kubrick]
State of Siege (counter-revolution, Uruguay)[Constantin Costa-Gavras]
Sword and Scalpel (Canadian doctor helps Chinese Communist revolution)
Vukovar (Bosnian War)
Wargames (nuclear nightmare)
Z (civil war in Greece) [Constantin Costa-Gavras]