The founding fathers limited the powers of each branch of government so one doesn't get powerful. If one got too powerful it could lead to a dictatorship, which none of them wanted.
The three separate branches limit one another through a series of checks and balances. The framers wanted to make sure that the branches were equally powerful, so they set up rules that enable each branch to stop the others from doing some things.
The focus was on expansionism, the United States took little part in foreign affairs for much of the 1800s. Committed to the policy of isolationism, the U.S. declined to intervene in an independence movement in Poland when asked to do so by foreign leaders.
Throughout Reconstruction, Southern whites felt threatened by legislation to provide rights for former slaves. The Civil Rights Bill of 1875 was the last rights bill passed by Congress during Reconstruction.
