Eastern Prince William supervisors responded sadly Tuesday night to the resurfacing of the old east-west split. "I don't think I've ever heard so much animosity to the community as I've heard tonight," said Dale City's James J. McCoart.

McCoart asked the skeptical western farmers to believe the board was acting in the entire county's interest. "We're faced with a jurisdiction that has the capability of coming in and taking what's yours."

Prince William County, which has no housing authority, few street lights and 1/20th the population density of Washington, could become a city.

The elected supervisors of the developing county south of Fairfax are considering a shift to city status to prevent Manassas and Manassas Park from annexing valuable chunks of the 337-square-mile county. Tuesday night the citizens got a chance to tell the supervisors what they think of the idea and they were not encouraging.

"I know there are a lot of people out there who think we have gone collectively nuts," Supervisor Donald Kidwell said after 21 speakers in a row had registered their opposition. Still, the county board voted 5 to 2 to pursue the idea.

The board first discussed city status last summer when Manassas, which is an independent city despite being the county seat, bought 229 acres of prime undeveloped land outside its borders. Convinced that Manassas has designs on all the land between the city and the increasingly busy Manassas Municipal Airport, county leaders began looking for protection.

They looked to the cities of Chesapeake and Virginia Beach, which were created in the early 1960s to foil the expansionist tendencies of Norfolk and Portsmouth. A Prince William study completed this winter called the idea feasible for the county, although the General Assembly and a majority of county voters would first have to approve the change. The study by annexation law specialist Robert C. Fitzgerald of Fairfax said becoming a city would protect Prince William's future.

"It's a question of revenue," said Prince William Board Chairman Kathleen K. Seefeldt. "Cities can annex. Cities do it all the time . . . We are vulnerable . . . "

Prince William's population increased by 54 percent from 1970 to 1980, to 145,000. The county is so young that more than 27 percent of its residents are in school, and supervisors are concerned that without the industrial base now being eyed by Manassas, the county's tax rate will skyrocket to provide schools and other services.

Most of the 70 citizens who drove their pickup trucks and cars through the rain to the courthouse in Manassas Tuesday night were farmers, friends of farmers and other residents of Prince William's rural west. They blamed the city idea on the supervisors from the east, where Dale City, Lake Ridge and other developments in the Interstate 95 corridor have attracted a younger, more mobile population.

"Put a line down Cedar Run," Alicia Bear, the 66-year-old wife of a farmer in Nokesville, urged the board. "Give everything east to Dale City, and leave us the county."

"You are asking these people to sign away their heritage for a pot of porridge," agreed Fred J. Fees, president of the Prince William Farm Bureau. "Our citizens in the west have been disenfranchised of their county government . . . there is now no longer a community of interest existing in our relationship. I plead you go your separate way."

Fees and other opponents said city status would erode a property owner's rights, since landholders near Manassas and Manassas Park would not be able to petition for annexation. They also charged that city status would increase taxes for everyone in the county.

Supervisors acknowledged the tax rate would rise -- from the current $1.45 per $100 of valuation to about $1.61 -- because the city would have to assume responsibility for its roads from the state highway department. Supervisors in Prince William, like politicians throughout Northern Virginia, long have believed the highway department neglects their fast-growing region, and they believe they could do a better job of managing the road system.

Fairfax County has considered becoming a city from time to time, and Supervisor