Manufacturing, production and efficiency had increased through necessity during the Great War. America had emerged as a world industrial leader and the US economy was booming, profits were increasing which led to the period in American history called the Roaring Twenties with a massive rise in consumerism for the wealthy.
Plessy vs. Ferguson was a Supreme Court case that took place in 1896. It all started when Homer Plessy, a man who is 1/8th African American, was asked to move from his seat in the all white section of a train car. Plessy refused to move since he had bought a seat in this section. He was promptly arrested for his refusal to abide by this law.
Homer Plessy would go on to change this law saying that it was unconstitutional. His lawyer argued that this was a violation of his 14th amendment rights. However, the Supreme Court ruled against Plessy. The majority opinion from the Supreme Court stated that this did not violate the 14th amendment as long as the facilities for blacks and whites were "separate but equal."
This ruling drastically changed American society, as other businesses and facilities became segregated by race. These laws would last for almost half a century in the United States.
Yes because Thomas Paine wrote a pamphlet called Common Sense which actually inspired the Declaration of independence . Thomas Jefferson used it as a template when he wrote the Declaration of Independence, distilling many of Paine's ideas -- the natural dignity of humanity, the right to self determination.