The reason why Great Britain and France declared war on Germany at the beginning of the second World war was because A - The invasion of Poland.
When Germany invaded Poland this was the beginning of what would later be called the second World war. A tense atmosphere was brewing up in Europe for a few years since then already because when Hitler's party took charge of Germany, it increasingly militarized the country and was preparing it for war.
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.
They would agree with segregation is illegal because the constitution grants all equal rights.
Possibly, though I can't really say.
