The Jim Crow era directly followed the Reconstruction period in the United States history. The name Jim Crow comes from a white actor who portrayed a dim witted black slave in the 1830's. Jim Crow is used to describe segregation laws, customs, etc.
Made them unhappy I would think.
Washington's farewell address called for "no entangling alliances". In other words, stay out of foreign affairs. Washington saw his own cabinet torn apart by differing views of certain European nations. He also warned against political parties. Again his own cabinet was ripped apart due to strong political feelings and refusal to compromise. He saw political parties as the first step in dividing a nation that had just begun.
I’m 90% sure the main idea of Truman’s statement is that they should never be used in war because of the unnecessary total destruction of virtues and killing of 100,000’s of innocent civilians