MIAMI -- Lawton Chiles, who rejected big-money politics while running in one of the nation's costliest gubernatorial contests, appears to be coasting toward victory in Florida's Democratic primary Tuesday.

The former senator limited his campaign contributions to $100 and seems to have held off a nearly $6 million bid waged by his Democratic rival, Rep. Bill Nelson.

But Chiles's lofty notions of revolutionizing American electoral politics through a "people's movement" campaign may prove to be overblown. His base support appears to come from the status he enjoys among voters as an 18-year veteran of the Senate, not from his self-imposed diet from large campaign contributions. He made a series of missteps in mid-summer that a lesser known and less beloved candidate might not have survived as easily.

As a result, the main benefactor of Chiles's campaign experiment could be Republican Gov. Bob Martinez, who has only nominal primary opposition and is waiting in the wings to take on Chiles and his revolution with a $12 million reelection kitty, a professional campaign staff and a huge television advertising budget.

Earlier in the year, Democrats considered Martinez, Florida's second Republican governor since Reconstruction, an easy mark. But after the scrappy Democratic primary, Martinez will be more difficult to dislodge from office.

Chiles, 60, blunted Nelson's well-crafted TV attack ads and defused the potentially explosive issue of his health by openly discussing his bouts with depression and his treatment with the widely prescribed antidepressant drug Prozac. But Nelson's constant jabs on those two issues left bruises on Chiles that will linger.

The stakes in the race are high. As the nation's fourth-largest state, Florida stands to pick up four congressional seats after the 1990 census. The Republicans hope to hold onto the governor's mansion, and take control of the state Senate for the first time in this century, putting them in position to control the legislative redistricting process.

With all the action on the Democratic side of the ticket, Martinez was free to do a series of soft television ads that portrayed him as the environmental governor, the crime-fighting governor and the family man.

The two Democrats had few differences on the issues to distinguish one from the other. Chiles, with his anti-campaign campaign, constantly chided Nelson for accepting campaign contributions from special interests. Despite his self-imposed contribution limit, Chiles raised $1.9 million from 34,000 contributors.

Nelson, meanwhile, staged a classic modern media campaign with an operation that purred with efficiency. The 47-year-old congressman suggested at one point that Chiles was a little too sanctimonious about campaign ethics, and attempted to throw the ethics questions onto Chiles's back with an attack on Chiles's handling of several business deals.

Under siege, Chiles's campaign lost momentum and he began to slip in the polls. In early August, when Chiles revealed he had resumed the use of Prozac after declaring his depression "cured" last April, there were new demands that he release his medical records.

Then Nelson's surge waned. The resurrection of Chiles's depression as an issue forced the retired senator to release his medical records -- a step he had resisted since April. But the thick stack of records contained only mundane medical information, defusing the issue.

"Bill Nelson's tide came in, and Bill Nelson's tide went out," said Robert Joffee, director of the Mason-Dixon Opinion Research poll, an independent Florida polling firm whose latest survey showed Chiles up by 18 points.

Last week's final debate between the Democratic rivals was so anticlimactic that few obervers expect it to have any impact on the race.

The campaign debates were another example of Chiles's hopes to change U.S. politics. When Nelson pressured him to debate frequently, Chiles agreed to meet "mano a mano," in the tradition of Lincoln-Douglas. Four of their five encounters were one-on-one matchups.

But at their final meeting, in Boyton Beach on Florida's southeast coast, the spirit of those clashes between Lincoln and Douglas was nowhere in evidence. There were no hard questions that forced either candidate to clarify and sharpen his positions. Nelson spent much of his time justifying his campaign strategy to attack Chiles, while Chiles lobbed softballs to Nelson that were designed to hit Martinez.

What did Nelson think of the governor's failures in education? What would Nelson do about violent crime, which statistics showed rose during the Martinez administration? Nelson agreed with criticisms of the governor. Yes, Chiles said, Nelson made fine suggestions about what to do when Martinez is out of office.

Toward the end of the debate, Nelson noted that he had put on a series of 30-second TV spots to inform voters of his positions on various issues. Chiles had no ads on these issues and Nelson speculated that Chiles's TV spots were just another example of his failure to spell out his positions to the voters.

Chiles smiled his best anti-campaign smile as he replied, "Well, as you know, Brother Bill, most of my TV ads have been required to answer your TV ads."