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the domino theory
Soviet/Communist containment.
the great society
Containment.
Hugh Pemberton has written: 'Policy learning and British governance in the 1960s' -- subject(s): Economic policy, Politics and government
detente
Domestic and foreign policies reflected 1960s US nationalism through Inter-American machinery product and Latin American trade.
Up until the 1960s, the racial policy of America was that there should be a strict separation of the races. This policy was unfair and, in a lot of ways, extremely cruel.
because it was a new type of fish and it tasted so nice
It was inconsistent with civil rights awareness.
Prior to World War II, American foreign policy was isolationist. We felt that other nations problems, particularly their wars, were their own business and we avoided getting involved unless we felt directly threatened. As a result of WWII though we decided that threats to peace and freedom elsewhere in the world did affect us, that if we ignored serious trouble in the world it would probably eventually find us. Thus after the war we became internationalist using our power and prestige to help and protect our friends and acting to prevent wars wherever possible or to minimize them when they did break out. Another issue that drove foreign policy post WWII was the spread of communism from both the Soviets and Chinese. No longer could the US afford to be isolationist. The African continent saw decolonization and by the 1960s the fight was under way for countries between democratization and Marxism. Therefore the US supported autocracies and not "freedom fighters" generally aligned with Marxist regimes. After the second world war, the US emerged as the a "super power" its economic infrastructure was untouched by the war and the US was the only nation with an atomic bomb. Based on these factors and the ones cited earlier in this answer, US foreign policy was shaped upon the US's ability to have a huge influence on world affairs.
The US Treasury would exchange them for silver coins. That policy ended in the mid-1960s when silver coinage was discontinued.