Optimism. It's not a uniquely American quality, but it's a very American quality. And, for those who would be the president of the United States, it's a quality they can't afford to ignore.

Candidates must walk an unenviable line. They must sound a bit irascible without sounding impotent. Want change without trashing the country, address problems without being pessimistic, and deploy negative advertising without being perceived as nattering nabobs.

It's tough, which might explain why some candidates have taken to defining optimism down instead of living up to its sunny expectations.

When I was in New Hampshire the day before primaries, I attended a Hillary rally at which I was pleased to hear her talk about the accomplishments of America, past, present and future. It only took a moment to realize, however, that the "can-do attitude" she was talking about had nothing to do with the capabilities of individual Americans.

"It has paralyzed us," she said of the "politics of fear," engendered entirely by Bush and not by the world's 19 most notorious, murderous hijackers. "It has made us believe we can't solve our problems…Since when did America become the can't-do country? We roll up our sleeves and fix things…We have to know that anything is possible in America."

Hillary explained that President Bush had crushed the can-do spirit of America and the only thing that could bring it back, presumably, was the singular ability of the Clintons to propose giant government programs to do things for them. Are you following? Neither am I.

Which is why I was saddened to hear a similar message coming out of Mitt Romney's win in the Michigan primary.

"Tonight marks the beginning of a comeback, a comeback for America," Romney said to supporters in Michigan. "Tonight is a victory of optimism over Washington-style pessimism."

Hey, I'm all for optimism, but the difference in McCain's and Romney's messages in Michigan seemed to be more about giant checks from the federal government than good cheer and competence.

McCain, with his characteristic and often tin-eared "straight talk," told Michigan voters the old jobs weren't coming back, but that fiscally responsible government and lower tax rates could make Michigan and the whole U.S. a place hospitable for new business in a global economy.

Romney promised a surge from $4 billion to $20 billion in federal spending on energy research, which he said was not a "bailout, but a workout," as the center of his plan, embellished with some regulatory scale-backs on fuel efficiency standards.

Though Romney's plan arguably could have an effect on the national security issue of energy independence and industries beyond the auto industry, as he argued on Fox News Sunday, the idea that government-funded research is the key to keeping automotive jobs is belied by the economy of another early primary state in economic transition—South Carolina, which McCain won despite sticking to the assertion that "people know those textile jobs aren't coming back" and promises of "tough times ahead."

The truth is that South Carolina's textile industry has been replaced, in part, by its own automotive boom thanks not to government investment, but mostly to the non-unionized, skilled workforce of the South coupled with good quality of life, and population growth, all of which are fueled by lower tax rates and less oppressive regulations than Michigan boasts. Continued...