International relations in the twentieth century: world wars and the Cold War
Concepts: alliance systems; militarism; imperialism; nationalism; the July Crisis (1914); the Treaty of Versailles (1919); collective security and the League of Nations; appeasement; total war; the United Nations (1945); superpower rivalry; containment; the Truman Doctrine and Marshall Plan (1947); NATO and the Warsaw Pact; the Berlin blockade (1948-49); the Cuban Missile Crisis (1962); détente; non-alignment and the Bandung Conference (1955); proxy war.
Two organising ideas: first, the shift from a European balance of power to a bipolar world dominated by the USA and USSR; second, the efforts of newly independent states to escape that bipolarity - and their transformation into battlegrounds when they could not.
Traps: single-cause answers ('the alliance system caused the war'); confusing the League with the UN, or assuming either was powerless in every case; explaining the Cold War purely as ideology while ignoring security fears, nuclear weapons and economics; treating African states as passive, when Angola and Mozambique show local conflicts entangled with superpower patronage; assuming détente ended the Cold War without pressure from within the Eastern bloc.
Rule of thumb: sort causes into long-term structures, short-term decisions and crises, and the trigger event; then weigh them explicitly. For consequences, separate political, economic, social and psychological effects.
Worked example: 'Why did the Cuban Missile Crisis not become a war?' The long-term arms race created strong pressure against direct confrontation; the short-term secret deployment of Soviet missiles produced a crisis once a U-2 flight photographed them; the trigger was Khrushchev's decision to send them. Resolution came through both public and private diplomacy - withdrawal in exchange for a public American pledge and a secret pledge over Turkey.