Prince William officials have suspended their review of a proposed Nokesville horse racetrack until Virginia's attorney general clarifies whether off-track betting would be permitted there.

The move means the first public hearings and Planning Commission vote on the grass track proposed by Middleburg developer James J. Wilson could be delayed several months. But it also shows that public opposition to the proposal--and to the plans of Colonial Downs Inc., which wants to build in Dumfries--are swaying local officials.

Wilson would stage live horse races at his 1.5-mile track 90 days a year. Colonial Downs has proposed just 20 days of live racing at the track its wants to build atop a commercial landfill off Interstate 95 in Dumfries. But inside the grandstands, fans could bet every day on horse races from around the world on simulcast television.

Track opponents, who have mounted a grass-roots campaign to stop both facilities, say they did not approve off-track betting when they voted five years ago to allow racetracks in Prince William County. Del. Robert G. Marshall (R-District 13), contending that an off-track operation would thus be illegal, has taken his case to Attorney General Mark L. Earley (R).

"Unless it was invisible ink on the ballot, the voters approved on-track betting, not off-track betting," Marshall said.

"The law is very clear," Wilson said. "What Bob Marshall has done, in order to garner votes, is ask for an opinion for which the answer is already known."

Earley spokesman David Botkins said Marshall's request is "in the mix" of hundreds of opinions awaiting clarification. A ruling could take 90 days.

Both applicants need off-track parlors to make their tracks profitable and cover the cost of money-losing live meets. Many Prince William residents oppose gambling as immoral.

Until they know what's allowed, county planners say they can't conduct a full land-use review of the 1.5-mile track Wilson's firm, Equus Gaming Co., wants to build on 220 acres near the Fauquier County line.

The property is zoned for a racetrack, but Wilson needs a special use permit. That means county planners can impose conditions on the track's operation.

"Simulcasting is part of the application," said planner Lisa Fink, who is overseeing the application. "We need to know if we can create conditions to offset the impacts of simulcasting. . . . It would be helpful for us to have a decision before we craft those conditions."

Fink noted that public opposition also drove the decision to hold off. "We've had county residents who are raising the issue, and we have an obligation to hear their concerns," she said.

Wilson said the delay is unlikely to be a setback for him, because the Board of County Supervisors, acting on recommendations from the county's Planning Commission, will not consider his track until at least January, after the November election. But he said the law Virginia approved 11 years ago allowing betting on horses clearly permits simulcasting.

Prince William is the only Northern Virginia jurisdiction to approve parimutuel betting at the polls, in 1995 and 1989. The referendum's language did not specify simulcast betting but addressed only a racetrack. State racing officials say state law allows off-track wagering as long as it's at a live racetrack.

"Simulcasting is one of the functions that goes on at a racetrack," said Stan Bowker, secretary to the Virginia Racing Commission, which regulates Colonial Downs's existing track southeast of Richmond and will hold hearings Tuesday on the two new applications.

Because simulcast betting is part of a track's operation, such as hours and location, it would not be addressed in the language of a ballot question, he said.

But Bowker said officials aren't as sure whether Colonial Downs can run its off-track parlor for two years before the track's grandstand--proposed to open in 2003--is built. The company is counting on proceeds from off-track wagering to partially fund construction of the track.

"They'll have to address that," Bowker said.

Dumfries officials are proceeding with their planning review of the steeplechase track Colonial Downs wants to build in their town.

"We're just moving ahead," said Town Manager Michael Riley. "If one person wants to ask for an opinion, they're entitled to that, but the understanding the town has is that simulcasting is a permitted condition."

The town is converting the kinds of business permitted at the landfill to include a racetrack. The Town Council, after holding hearings on Colonial Downs's application for a special use permit, is likely to vote for the track early next month.