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I Indeed, Kenneth Arrow’s “impossibility theorem” shows that there is no mechanism for making collective choices, other than dictatorship, that translates the preferences of diverse individuals into a well-behaved social utility function. Nor has any electoral rule been found whose results cannot be manipulated either by individuals voting insincerely—that is, casting their ballots strategically for less-preferred candidates or issues in order to block even worse outcomes—or by an agenda setter who controls the order in which votes are taken.Elections studying collective decision-making by committees, Duncan Black deduced what has since been called the median-voter theorem. If voters are fully informed, if their preferred outcomes can be arrayed along one dimension (e.g., left to right), if each voter has a single most-preferred outcome, and if decisions are made by simple majority rule, then the median voter will be decisive. Any proposal to the left or right of that point will be defeated by one that is closer to the median voter’s preferred outcome. Because extreme proposals lose to centrist proposals, candidates and parties in a two-party system will move to the center, and, as a result, their platforms and campaign promises will differ only slightly. Reversing 1964 presidential hopeful Barry Goldwater’s catchphrase, majority-rule elections will present voters with an echo, not a choice. If the foregoing assumptions hold, the median voter’s preferences also will determine the results of popular referenda. As a matter of fact, anticipating that immoderate proposals will be defeated, the designers of ballot initiatives will strive to adopt centrist language, in theory moving policy outcomes closer to the median voter’s ideal point than might be expected if decisions are instead made by politically self-interested representatives.