In praise of manipulation

Many theorists believe that the manipulation of voting procedures is a serious problem. Accordingly, much of social choice theory examines the conditions under which strategy-proofness can be ensured, and what kind of procedures do a better job of preventing manipulation. This article argues that democrats should not be worried about manipulation. Two arguments against manipulation are examined: first, the 'sincerity argument', according to which manipulation should be rejected because it displays a form of insincere behaviour. This article distinguishes between sincere and non-sincere manipulation and shows that a familiar class of social choice functions is immune to insincere manipulation. Secondly, the 'transparency' argument against manipulation is discussed and it is argued that (sincere or insincere) manipulation may indeed lead to non-transparency of the decision-making process, but that, from a democratic perspective, such non-transparency is often a virtue rather than a vice.