Answer
1. Though Madison argued for a large and diverse republic, the writers of the Federalist Papers recognized the need for a balance. They wanted a republic diverse enough to prevent faction but with enough commonality to maintain cohesion among the states.
2. Madison believed that keeping the three branches separated was fundamental to the preservation of liberty. He wrote: "The accumulation of all powers, legislative, executive, and judiciary, in the same hands, whether of one, a few, or many... may justly be pronounced the very definition of tyranny."
3. To Promote Constitution for support. The purpose of the Federalist Papers? Persuade Americans that the system of government established the Articles of Confederation was not working.
4. For many historians, Madison is a puzzle: "the Father of the Constitution," co-founder of the Democratic-Republican Party, and brilliant secretary of state under Jefferson, yet he is not rated as a spectacular President. Part of the explanation for this contrast has to do with Madison's personal strengths. He is said to have been a master of the small arena. Studious, keenly political, and a perceptive judge of men and issues, Madison could shape constitutions and influence legislation with few peers, but he was too cautious for the kinds of presidential leadership that left clear marks upon the political landscape. Moreover, unlike the tall, statuesque Washington and Jefferson, Madison's shorter-than-average body seldom dominated the scene. Even the very short John Adams, with his rocklike character, had exuded authority, yet among his contemporaries, Madison had trouble outshining anyone else in the room. Behind the scenes, in small intimate groups, few men, however, could resist his sharp mind or his persuasive reasoning.
PS. sry if the last questions answer was too long