In fact, it was settled centuries ago that for preservationof liberty and prevention of tyranny it is absolutely essential tovest separate powers in three different organs. In Federalist47, 48, and 51 James Madison details how a separation ofpowers preserves liberty and prevents tyranny. In Federalist47, Madison discusses Montesquieu's treatment of theseparation of powers in the Spirit of Laws (Boox XI, Ch. 6).There Montesquieu writes, "When the legislative and executivepowers are united in the same person, or in the same body ofmagistrates, there can be no liberty. . . Again, there is noliberty, if the judicial power be not separated from thelegislative and executive." Madison points out thatMontesquieu did not feel that different branches could nothave overlapping functions, but rather that the power of onedepartment of government should not be entirely in the handsof another department of government.