The 17th Amendment (C) established the system of direct elections of Senators by the voting public. This changed the system whereby these individuals were previously elected by state legislatures.
On August 6, 1945, during World War II (1939-45), an American B-29 bomber dropped the world's first deployed atomic bomb over the Japanese city of Hiroshima. The explosion wiped out 90 percent of the city and immediately killed 80,000 people; tens of thousands more would later die of radiation exposure.
From what I can remember, states' rights was a large factor contributing to the Civil War. With Lincoln becoming president and representing the North, the Southern states seceded, leading to a war. The state governments of the South argued that since the Constitution and the federal government was created by the states, the federal government had no right to stop states from seceding. President Lincoln and other northerners disagreed and wanted to preserve the Union by stopping states from seceding.
After the war, I believe the South still disagreed on a strong federal government. They wanted to rule the area by themselves.