<em>Jim Crow laws.</em>
Explanation:
After the Civil War, segregation in the South was still very prevalent. Jim Crow laws were all over the South and were made to keep African-Americans and white people separate. Some of these laws included things like separate schooling for white and black children, different prisons, separate ticket booths, etc.
Black codes were also a very common thing in the South. These were much more harsher than Jim Crow laws and made it very hard for African-Americans to do anything in everyday life. Many would get arrested for no real reason. Voting laws were also very common as well, so many African-Americans could not vote.
Years and years of protesting these unequal doings, Jim Crow laws, along with other segregative laws and measures, became illegal.
The sinking of the Lusitania in 1915 had a very negative effect on the American public opinion of Germany, since it was the Germans who sank the American ship for seemingly no reason.
The answer to this question is C-trade rights.
