PAUL TSONGAS, SO FAR THE ONE AND only Democrat brave or foolish enough to run for President, went on a tiny campaign swing in Iowa not long ago. Iowa, of course, is traditionally the first test for presidential hopefuls. Every four years, before the corn peeps up, the state sows a few dragon's teeth, and warlike Democrats spring up and try to slay each other. But not this season. On the long drive between Sioux City and Fort Dodge with his entourage—his lively 9-year-old daughter, Molly, and a campaign worker—Tsongas was the loneliest of long-distance runners. There was nothing to see out there but the unfruitful April fields. No crops. No candidates. Nothing.

"Don't worry, Daddy," said Molly from the backseat. "The sun and wind and clouds will vote for you."

Naturally, the 50-year-old former U.S. Senator from Lowell, Mass., won't always be campaigning in such a void. Virginia Gov. Douglas Wilder has put out feelers for a possible candidacy; other names are mentioned—among them, New York Gov. Mario Cuomo and Sen. Albert Gore of Tennessee. But by and large—despite President Bush's recent arrhythmia—Democrats seem to feel that offering up a 1992 presidential candidate will be like tossing a virgin into the volcano. As one veteran of earlier futile Democratic presidential campaigns puts it, "Bush looks invincible."

So it's a puzzle why Paul Tsongas (pronounced "Song-gus"), a soft-spoken man with a sort of droop-eyed sense of humor, would challenge the odds. He has begun his journey of a thousand miles, he says, for two reasons: to rescue the American economy and, in the process, to slap some sense into the Democratic Party.

"I want to make our party pro business once and for all," he says. "In the core values of civil rights, women's rights, the environment, I'm a liberal—always will be. But my focus now is to make this the party of economic regeneration. A place where the average businessman or woman can be comfortable." Right now, Tsongas believes, the American economy is full of rot. "The No. 1 problem, by far," he says, "is our declining industrial competitiveness." He wants to reduce the capital gains tax on business investments. He wants to loosen antitrust laws to help research. He wants to be "the economic Paul Revere."

The question is, will people rush to their windows and heed him? Tsongas has made much the same pitch for years—to no avail, he admits. Now, with a start-up staff of 14 and about $450,000 in contributions, what makes him think things will be different?

"Having lost so much, the Democrats are thirsting for a new formula," says Tsongas. "And I think I can rally the country." The former Senator is also propelled by a service ethic driven home during a stint in the Peace Corps. He loafed through Dartmouth. He didn't enjoy Yale Law School. But teaching high schoolers in Ethiopia was, he says, "by far the best two years I've ever spent professionally." Beyond that, he is motivated to run for President because of his other watershed experience: nearly dying of cancer.

In 1983 Tsongas, then 42, was diagnosed as having a cancer of the lymph nodes. Doctors gave him eight to 10 years to live. "At first I was immobilized," he says, sitting now on the sun-splashed porch of his big Victorian house in Lowell. "You're talking to somebody who didn't smoke or drink. Who ran..." After two terms in the House and one in the Senate, Tsongas announced he would not seek reelection in 1984, in order to spend more time with his wife and daughters. Over the next couple of years, he got very sick.

"I remember looking out my hospital window at Fenway Park," he says. "One night this friend of mine, an unofficial uncle to my girls, took them all to a game. I lay there watching the lights of the ballpark. Strange feeling. Like watching what the world would be like without you."

What saved Tsongas was a then-experimental bone-marrow transplant in 1986. His chief physician, Dr. Tak Takvorian, of Boston's Dana-Farber Cancer Institute, says the ex-Senator "is in superb health now. If you get beyond one year [after the transplant] and are still healthy, then your success rate in terms of curability of the cancer goes up to 80 or 90 percent or higher."

Now, "from my perspective as a lab rat," says Tsongas, he supports catastrophic health-care coverage for all, having seen how crushing the bills could be for some. As the campaign waxes, he also figures to become a role model for the many Americans—one in four—who have or will have cancer themselves. "A lot of them may disagree with me violently on the issues," he says, "but they will take comfort in the fact that I'm out here."

And in a Speedo. To help quash the health question, Tsongas has again taken up swimming, a sport he lettered in at Dartmouth. Last month he competed in the YMCA National Masters Swim Championships in Indianapolis in the 50-to-55 age group, and didn't finish last.

But more important, brushing death has affected his politics. "You have a sense of how short life is," he says. "It's like returning to the primitives' view of earth and family and generations." Now he is loath to leave his own family—wife Niki, 44, and daughters Ashley, 17, Katina, 14, and Molly—to campaign. That's why he took Molly to Iowa. Generational thinking also underpins his concerns about education and the environment. "I would take global warming very seriously," he says, "unlike Bush. He's generationally immoral in his policies."

At the Best Western Starlite Village in Fort Dodge, they served up a big old Sunday breakfast. Forty or 50 of the Democratic faithful showed up to tuck into it and to hear the former Senator speak. They liked him. But they weren't shy about poking his political weaknesses.

"After years away from Washington, aren't you out of the loop?"

"I like what you say, but can you stir passion in people? I'm still waiting to see some fire."

"What about the Dukakis problem?"

The Dukakis problem being that Tsongas is, like the 1988 Democratic nominee, a Greek-American liberal from Massachusetts and as such, food for Jay Leno. Son of a dry cleaner in Lowell—Tsongas as a boy worked in the store making hangers—the ex-Senator is proud of his heritage. Still, it's an unhappy coincidence that so far ("Excuse me, you forgot your albatross") he must carry everywhere he goes.

His long absence from Washington, D.C.? Tsongas is trying to turn that into an asset. He likes to talk about the corporate lawyering he has been doing and the boards he has been serving on. He says he now understands the way business people think.

As for what might be called "the fire thing":

"I'm used to people discounting me," he said. "Then when I win, they can't figure it out." But to win in '92, Tsongas is going to have to lift folks out of their seats. A lot of them will want to know that in the event of war, he can be counted on to provide more great Persian Gulf-style TV.

If Cuomo or Sen. Bill Bradley of New Jersey should enter the race, they would likely swamp Tsongas' efforts. Still, these days, under white-hot press scrutiny, even the strongest-looking candidate may falter. So maybe this very dark horse has a chance. Anyway, that's the sound of his hooves out there in the Democratic night.