Because it was so large, corruption ran rampant and politicians and senators often had their own interests at heart. The sheer size of the empire also made it hard to control, with many revolutions and uprisings popping up. The cultural diffusion was also an issue, as many different people and cultures were all under one banner, so infighting was pretty common, epically the further you get away from Italy.
As a reaction to the attack on Pearl Harbor in 1942, President Roosevelt authorized Executive Order 9066, by which Japanese-Americans were deported and incarcerated in the interments camps. They were viewed as a threat to national security.
D. Almost 3,000 people being killed.
Fredrick lll of Denmark <span />
It contributed to sectional tensions because the north and south had grown further apart in terms of economy, idealology and society.