What are the major duties of Congress in the American system? How does Congress go about fulfilling these duties?

What are the major duties of Congress in the American system? How does Congress go about fulfilling these duties?

What are the qualifications, terms, and duties of Senators and Representatives? What accounts for any discrepancies between the two?

What are the roles that the President must fulfill while in office? How do these roles sometimes conflict with one another? How does the Executive Office of the President help mitigate some of these conflicts?

What are the sources of presidential power? How has this power changed over time?