The main idea that madison addresses is why the us government

James Madison addressed the needs for a stronger constitution.  He believed what was need was a constitution that could effectively rule the colonies that includes both the majority and minority with fairness. This way there would be more control and the government had more strength rather than letting states’ rights prevail.

answer; by working independently, the states have a high likelihood of developing innovative solutions that can be employed in other states;

"harry t. moore (1905-1951) – civil rights activist, leader, and the first martyr of the civil rights movement. fannie lou hamer (1917–1977) – leader in the american civil rights movement; co-founder of the national women's political caucus and freedom democratic party. james farmer (1920–1999) – congress of racial equality."