The United States Constitution, signed on September 17, 1787, is structured into three parts: a preamble, seven articles, and 27 amendments, which together establish the framework of the government. It operates on seven guiding principles: popular sovereignty, republicanism, federalism, separation of powers, checks and balances, limited government, and individual rights, ensuring that the government respects the rights of citizens. These principles stem from historical documents and philosophical influences, highlighting a reciprocal relationship between the government and the people it serves.