Federalism and the separation of powers

The most important institutional features of American government – federalism and the separation of powers. Federalism divides power into two levels (national and state). The separation of powers divides each level of government against itself (legislative, executive, and judicial branches). After learning more about these two features respond to the following:
Describe at least one pro and one con of federalism now and at an earlier time in history.
Why is it necessary for people in the United States to have a national and state government?
Why has the separation of powers become a crucial feature of the American government? In your response, reflect on how these two features have been interpreted within our modern-day governmen