The US introduced industrial power and new weapons. To protect their country from being taken over by the US or another foreign power, Japan decided to become a "western" power. The US opening Japan to trade exposed them to the methods of a modern country.
Climate change that caused a severe drought.It is also theorized that the Hittite's cities were destroyed by earthquakes.
According to Richard Neustadt landmark book,"Presidential Power" he argued that the president's most fundamental power is the power to persuade. He said "Effective influence for the man in the White House stems from three related sources: first are the bargaining advantages inherent in his job with which to persuade other men that what he wants of them is what their own responsibilities require them to do. Second are the expectations of those other men regarding his ability and will to use the various advantages they think he has. Third are those men's estimates of how his public views him and how their publics may view them if they do what he wants."
