After spending a lifetime in politics John C. Calhoun (U.S. Senator, Vice President of the United States, Secretary of War) wrote his brilliant treatise, A Disquisition on Government, which was published posthumously shortly after his death in 1850. In it Calhoun warned that it is an error to believe that a written constitution alone is sufficient, of itself, without the aid of any organism except such as is necessary to separate its several departments, and render them independent of each other to counteract the tendency of the numerical majority to oppression and abuse of power (p. 26). The separation of powers is fine as far as it goes, in other words, but it would never be a sufficient defense against governmental tyranny, said Calhoun.
Moreover, it is a “great mistake,” Calhoun wrote, to suppose that “the mere insertion of provisions to restrict and limit the powers of the government, without investing those for whose protection they are inserted, with the means of enforcing their observance, will be sufficient to prevent the major and dominant party from abusing its powers” (emphasis added). The party “in possession of the government” will always be opposed to any and all restrictions on its powers. They “will have no need of these restrictions” and “would come, in time, to regard these limitations as unnecessary and improper restraints and endeavor to elude them . . .”