Read the excerpt written by James Madison in Federalist #51. If men were angels, no government would be necessary. If angels were to govern men, neither external nor internal controls on government would be necessary. In framing a government which is to be administered by men over men, the great difficulty lies in this: You must first enable the government to control the governed; and in the next place, oblige it to control itself.
This argument supports which principle incorporated into the U. S. Constitution?

anarchy
federalism
checks and balances
popular sovereignty