Question

Why did crises like the Cuban missle crisis , the Vietnam war , or the Berlin Wall crisis not develop into war

Answer 1

The threat of mutual-assured destruction was enough to keep us from war (us is referring to NATO and Warsaw Pact nations).

Answer 2

The Vietnam war was a developed war. The Cuban Missile Crisis was a part of the Cold War, when USSR began building nuclear missile bases in Cuba. This was a problem because the missiles could reach important U.S. cities. The Berlin Wall was also technically a result of WWII.