For months, Democrats have been salivating at the prospect of unseating Rhode Island's three-term Republican governor, Edward D. DiPrete. Weakened by scandals, DiPrete won by a scant 7,000 votes in 1988, and since then the regional economic recession has forced a series of unpalatable budget cuts. In May, he was forced to ask for a sales tax increase -- seemingly the final nail in his political coffin.

But while DiPrete faces only nominal opposition in Tuesday's GOP primary, the three-way Democratic primary has turned into such a nasty fight that the survivor seems certain to carry scars into the fall campaign. Providence Mayor Joseph R. Paolino Jr., 35, the early favorite and party-endorsed candidate, has been under continuous battering from investor-entrepreneur Bruce Sundlun, 70, the candidate who faced DiPrete in 1986 and 1988. Warwick Mayor Francis X. Flaherty, 43, less well-financed and regarded as the long shot, said both his rivals are vulnerable to GOP counterattack.

The Paolino-Sundlun hostilities reached a crescendo last week in television ads and debates, with Paolino charging that Sundlun's business career was built on "junk bonds" and Sundlun accusing the mayor of showing favoritism in city contracts and coddling well-connected criminals. Polls last week showed Sundlun riding his status as a non-incumbent, non-career politician into a slight lead over Paolino, with Flaherty in third place but rising.

After a particularly bitter exchange during and after Thursday night's radio debate, Paolino announced Friday that he was pulling his negative ads in favor of messages about his plans and policies. Sundlun, however, introduced a new anti-Paolino ad, and Flaherty aired a message blaming his rivals for what happened to the campaign.

With some polls showing as many as 30 percent of the voters undecided, a neutral observer said, "With the negatives all of these guys are carrying, it's strictly a question of which one has the largest cadre of loyal supporters who will turn out -- despite what's happened."

The polls still show DiPrete trailing all three Democrats, but the governor has been on the air with a positive message the past week -- a sharp contrast to what the voters have heard from the other side.