Why? They win elections.
The most polarized campaign in history was between Adlai Stevenson (12.55) and Dwight Eisenhower (8.67) in 1952. Stevenson warned in accepting the Democratic nomination that "Sacrifice, patience, and implacable purpose may be our lot for years to come."
By contrast, in accepting the Republican nomination, Dwight Eisenhower promised to "seek out our men in their camps and talk with them face to face about their concerns and discuss with them the great mission to which we are all committed."
Can this kind of optimism be faked by spin doctors and speech writers? Only for awhile, says Fresco. Then the candidate's true nature will emerge. (It may, however, be possible to compensate for the errors of too much pessimism -- or too much optimism. See Living on the Sunny Side.) In 1988, University of Pennsylvania researchers released their first study of optimism and the presidential campaigns. Their conclusion -- that voters want an upbeat message -- appeared on the front page of The New York Times. Afterward, Michael Dukakis rewrote his convention speech.
It was a humdinger -- recalling the heady idealism of John F. Kennedy. Yet Dukakis couldn't hold this optimistic note, and in the debates began to slip back into his native pessimism.
The rest is history.
Valerie Andrews has written for Vogue, Esquire, People, Intuition, and HealthScout. She lives in Greenbrae, Calif.