"For centuries philosophers, mathematicians, political scientists and economists have searched for the best method of voting. Fifty-eight years ago the economist Kenneth Arrow (later a Nobel laureate) decided to see whether any voting rule could avoid the problems we've illustrated. Fix them all at once, he found, and you get--a dictatorship. One voter calls the shots every time. Arrow's "impossibility theorem" demonstrates that no system of voting always gives the "right" result."
Source: John Mark Hansen, Allen R. Sanderson, The Olympics of Voting, Forbes, June 3, 2009 (link)