After Vic Monia headed a campaign that helped persuade local voters to limit developments on surrounding hillsides, he immediately had to fend off a $40 million defamation suit filed by a developer. Citizens who crusade against local polluters or new developments are increasingly likely to be hit with such suits, called ``SLAPPs,'' or Strategic Lawsuits Against Public Participation, two University of Denver professors say. They say the suits are unconstitutional and discourage citizen participation. Some SLAPP targets, however, are SLAPPing back, with notable success. The suit against Monia, a computer engineer in Saratoga, Calif., never made it to court. Last year, nine years after it was filed, he won $200,000 in a countersuit when a jury ruled he was the victim of malicious prosecution. But the developer's SLAPP against Monia and his environmental and homeowners group had an effect. Intimidated city council members exempted the developer from some new restrictions and many local homeowners' groups disbanded, Monia said. ``I saw the impact of the lawsuit in the community: a lot less participation,'' he said. ``People were talking about: `You've got to be careful. You speak out, someone's gonna sue you.' ``I got so preoccupied,'' he said. ``I ended up leaving my job. I thought about moving out of the state. My daughters at the time were quite young, we'd just moved into a new home, the payments were pretty good-sized. And my wife said, `Are you sure you haven't risked everything we've worked for?' It really began to weigh very heavily on me.'' Now, he said, he'd think twice before participating in local politics. Monia's is one of hundreds of cases tracked by law professor George Pring and sociology professor Penelope Canan as part of a 2{-year study financed by the National Science Foundation. Pring and Canan say there are thousands more and the numbers have been growing since the 1970s, with the greatest concentration in areas with a high quality of life and a large number of educated newcomers, particularly California, New York and Colorado. Among the SLAPPs they studied: _A Louisville, Colo., woman circulated petitions opposing plans for a housing development on nearby farmland and was sued by the developer. _A Sutton, W.Va., blueberry farmer told federal authorities that operators of a nearby coal mine had polluted a river and killed fish in it. He was hit with a $200,000 libel lawsuit. _A group of citizens in Washington and Warren counties in New York went to court to block a planned trash incinerator and were countersued by the counties for $1.5 million. _The League of Women Voters in Beverly Hills, Calif., supported a ballot initiative to stop a condominium project and wrote two letters to a local newspaper criticizing it. The developer sued the league for $63 million. SLAPPs aren't meant to be won _ they're meant to intimidate, the professors concluded. They usually don't even get to court, and once there, more than 90 percent of the plaintiffs lose, Pring said. By that time, though, the citizen opposition often is scared off or into compromise, the professors said. The average SLAPP seeks $9 million in damages and takes 36 months to resolve. ``Hundreds of people we've talked to are literally terrified at the thought of losing their homes under multimillion-dollar lawsuits,'' Pring said. The suits also dissuade people who merely hear about them from participating in politics, he said. State authorities are starting to act. A legislative proposal in New York, for example, would require developers to prove actual malice on the part of citizen opponents before they could file SLAPPs, said Nancy Stearns of th New York Attorney General's Environmental Protection Bureau. ``It's troublesome,'' Stearns said. ``Particularly in the environmental arena, citizen participation is really key. The law relies on the involvement of citizens in the environmental process. It's not just exercising rights, but being a responsible citizen.'' She said the increase in SLAPPs in the last 10 to 15 years could be due to rising citizen concern about the environment. Pring and Canan said it also could be the result of a generally more litigious society, noting that many SLAPPs are unrelated to the environment but instead are filed by local or school officials against citizens or parents. In a recent case in suburban Denver, for example, a teacher accused by fundamentalist Christian parents of teaching witchcraft sued the parents for slander. Police officers have sued citizens who complained about their behavior, and elected officials have claimed defamation when citizens called for their jobs, the professors say. ``The right to tell our elected government representatives what we think and what we want them to do for us is the most basic right we have,'' said Pring. ``What is more basic than parents going to school with complaints about their children's education?'' Monia said he stewed about the ``injustice'' of the suit filed against him for almost a year after it was dismissed before deciding to sue the developer and the developer's attorney. In addition to the $200,000 jury award from the developer last year, Monia won an out-of-court settlement with the attorney. In a more prominent California case last year, a group of Kern County farmers who successfully fought off a SLAPP by agribusiness giant J.G. Boswell Co. in a water dispute countersued and won a $13.5 million judgment against Boswell for infringing on their constitutional rights. The court ruled Boswell filed the libel suit in 1982 to intimidate the farmers so they would not support a state proposition. ``Unlike SLAPPs, many SLAPP-backs are succeeding,'' said Pring, who testified on the farmers' behalf. ``It used to be filers could file these cases with impunity. ... Now I have to counsel would-be filers and their attorneys they may be walking themselves into a multimillion-dollar action.'' Still, he said, the farmers told him they would never again participate in politics. Monia, who said he was lucky enough to be able to weather nine years of legal bills, hopes his victory encourages others. ``And I hope that they can feel that if they go after individuals or companies who misuse the judicial system for political purposes, that they can win,'' he said.