1960s: Communist countries are considered the greatest threat to the United States and the free world, with Vietnam, Cuba, and the USSR at the helm.

Today: Although Communist countries like Vietnam and China still exist, most are looked upon favorably as allies and trading partners. Now so-called rogue states, or regimes that sponsor terror or are thought to be developing nuclear weapons—such as Iran, North Korea, and Syria—are viewed as threats to the Western world.

1960s: Socialism is frowned upon as a vile offspring of Communist ideologies. Capitalism is the driving force behind which democracy accelerates throughout the world.

Today: Although capitalism is still a driving force, socialism is far more widely accepted, with many developed countries in the Western world offering socialized medicine and adequate welfare for the needy.

1960s: The American Civil Rights movement to end segregation and discrimination in...