In Federalist 51, Publius argued in favor of "contriving the interior structure of the government as that its several constituent parts may, by their mutual relations, be the means of keeping each other in their proper places," asserting that "ambition must be made to counteract ambition" and dividing power between separate branches and between federal and state/local governments provided "a double security...to the rights of the people." Asserting that "the great security against a gradual concentration of the several powers in the same department, consists in giving to those who administer each department the necessary constitutional means and personal motives to resist encroachments of the others," Federalist 51 contended that "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. A dependence on the people is, no doubt, the primary control on the government; but experience has taught mankind the necessity of auxiliary precautions."