A clash over arts and public policy has been raging on two fronts in Fairfax County.

This Sunday, the Fairfax Choral Society, a private singing group, will drop Peter Schickele's "Missa Hilarious"--a spoof on the Latin Catholic Mass--from its concert at Fairfax High School following a threat by county supervisor Audrey Moore to kill the group's $2,478 county subsidy if it doesn't.

"We felt expediency was the better part of valor," said the group's music director, Robert E. McCord.

"They can do whatever they want as a private organization, but the government cannot participate in any way, shape or form in ridiculing anybody's religion," said Moore. She said that after she received calls about the program from outraged Catholics, she told McCord she would try to stop the group's county funding next year unless the piece were dropped.

In a separate battle, the Dance Exchange, a modern dance group, will perform Saturday as planned a controversial political "Docudance" at the taxpayer-supported McLean Community Center following a strong effort by the center's governing board to stop the performance.

"They didn't want it. They said they live in a strong defense community, a conservative community, and their board of directors was worried," said Dance Exchange artistic director Liz Lerman.

Officials objected particularly to one act in "Docudance" in which Lerman dances while unraveling a ball of string, "and I just keep unraveling it and keep talking about why nuclear war isn't going to happen."

The community center's executive director, Page Shelp, said, "We felt the juxtaposition of the performance coming right on top of Armed Forces Day Saturday was unfortunate." "We did not want it juxtaposed as if we were taking taxpayer money and making a specific statement."

However, she said, the 11-member board changed its mind after mediation by Peter Jablow, head of the Cultural Alliance of Greater Washington, an umbrella arts service organization.

Shelp said dropping the performance would have meant breaking a written contract. Lerman, who had consulted with an American Civil Liberties Union attorney, said she was prepared to sue to enforce the contract.

In the end, said Shelp, center officials "didn't want to make a federal thing out of it. That would create more controversy." She said the program would be performed Saturday in the center's 300-seat Alden Theatre, and that a disclaimer about the content of the program would be read.

In the case of the Fairfax Choral Society, music director McCord said he had been receiving calls from Catholics who were "incensed and offended."

The "Missa Hilarious" is one of a series of humorous musical pieces Schickele wrote as the fictional "P.D.Q. Bach," supposed to be the hapless son of the great composer. At one point, for example, a male voice interrupts the "Gloria" to sing, "I just met a girl named Gloria" to the familiar "West Side Story" tune.

According to McCord, there are many Catholics among the 100 members of the choral society and none regards the material as offensive. Nor does he.

But last Thursday, "it seemed like all hell broke loose. The phone just rang off the wall all day long." John F. Herrity, chairman of the county board of supervisors, called to express concern. Then Moore called with her warning of a funding cutoff.

"We felt we were in a no-win position at this point," said McCord, who quickly substituted another spoof--this one of 17th- and 18th-century Liebeslieder (German love songs)--for the "Missa Hilarious." "We hated to give in, because we are concerned about censorship of the arts. On the other hand, we don't wish to offend anyone."