The British Goverment gave polocies the the colonists because they wanted to still keep rule over America. They did this by sending taxes and rules.
The Federalist Papers were a series of documents, reportedly 85 different ones, that substantiated the ratification of the Constitution. Essentially made to defend it's ratification against the anti-federalists.
The reason we joined in world war one was due to the germans sinking merchant ships that had US citizens on them and they were also sinking some of our own ships. Due to that President Wilson involved us in the war.