BOSTON – I never dreamed that I would be feeling quite so cranky this early in the campaign season. Or that I would be driven from my usual sunny disposition to grumpiness by the Optimism Imperative.

Have you noticed that the second most overused word in presidential politics – right after “values” – is optimism?

Optimism is not just an attitude anymore, it’s an entire political platform. It’s as if both candidates were competing for Optimist in Chief.

The whole thing began, as far as I can tell, in February, that dourest of months, when Bush’s campaign manager said: “We’re moving into a phase where we will begin contrasting the president’s positive, optimistic vision with the alternative.”

Since then, Republicans have issued more warnings about pessimism than about terrorism. Bush has ritually described himself as “optimistic about America because I believe in the people of America.” The Republicans have run ads – going negative on negativism? – attacking Kerry as “still pessimistic, on a misery tour.” Dick Cheney, a walking, talking scowl of a man, has said “it’s a choice between President Bush’s hope and optimism and Sen. Kerry’s pessimism.”

And even after Kerry walked to the sunny side of the street for his running mate, the Bush/Cheney Web site warned: “Sen. Edwards delivers his pessimism with a Southern drawl and a smile.” He isn’t an optimist, he just plays one on TV.

Edwards himself once delivered a speech called “In Defense of Optimism.” And Kerry put out an ad, full of beaming children, saying: “We’re a country of the future. We’re a country of optimists. We’re the can-do people.”

The need to be seen as the Upbeat Candidate became institutionalized after 1987, when psychologist Martin Seligman’s research on campaign speeches concluded that the more optimistic candidate nearly always wins.

The Optimism Imperative usually cites a list of White House winners. Franklin Delano Roosevelt’s theme song in the midst of the Depression was “Happy Days Are Here Again.” Ronald Reagan made his sunny-ness into a slogan: “Morning Again in America.” And Bill Clinton was the ever-resilient Man from Hope. On the other hand, there was Jimmy Carter “malaise.”

I’ve never been quite sure how you judge optimism. Consider Reagan himself. Was “Star Wars,” his missile defense program, the product of a deep pessimism that we would always be living with a Cold-War enemy pointing nukes at us? Or was it the product of a cockeyed optimism that scientists could build a perfect shield?

As for Bush, who continually boosts his own optimism? One ad even says that “pessimism never created a job.” (Tell that to the defense industry.) Was it the pessimist Bush who accepted the bleakest flotsam and jetsam of intelligence to bolster war against Saddam? Or was it the eternal optimist Bush who believed that we’d be greeted with flowers?

For that matter, does the Bush view of a world divided into good and evildoers cheer you up? Or make you gloomy? Is the view that we should bring democracy to the world optimistic? Or foolhardy?

By the way, the Bush team still can’t decide whether it wins more points when voters are scared or hopeful. So we get alternating terrorism alerts and happy talk. Maybe this is what Oscar Wilde meant when he said, “The basis of optimism is sheer terror.”

The Optimism Imperative has infected both parties, but it actually comes in two strains: the ins and the outs. The “ins” attach optimism to the status quo and equate criticism with pessimism. The “outs” attach optimism to change.

John Kerry, who does not come across as a happy warrior – if he’s happy, said one wag, he ought to tell his face – has chosen as his campaign mantra a poem written by Langston Hughes during the Depression: “Let America be America again/Let it be the dream it used to be.”

In my book, any politician who thinks he can beat the odds and become president of the United States qualifies automatically as an optimist. With the possible exception of Ralph Nader. But I am not willing to concede that a candidate’s optimism is the political trump card. Attitude is no substitute for sober judgment. A cheerleader is not always a leader.

Some of our greatest accomplishments and some of our greatest disasters were all begun with optimism. The “can-do spirit” is fine and Yankee Doodle Dandy. But a leader needs to know the difference between what we can do and what we should do, and what we’d better not do.

That would give me reason for optimism.