Robert and Retha Morgan wanted their 17-year-old son Kurt St. Clair and his friends to have a safe high school graduation party on Thursday night, so they decided to let them celebrate at the Morgan home, on a secluded cul-de-sac just beyond the corporate limits of Vienna in Fairfax County.

Morgan, a public affairs director for American Telephone and Telegraph, and his wife, a vice president for the United Way of America, did what they thought was the right thing by posting "no alcohol" signs and inviting 25 adults to help monitor the 150 to 200 graduates.

As a member of SADD (Students Against Drunk Driving), Kurt rounded up nonalcohol drinkers to act as chauffeurs for those who did get their hands on beer.

If the Morgans had left the preparations at that, things probably would have gone just fine. But as an extra precaution, they notified the Fairfax County police and sought safe-party tips. Little did they know that plainclothes police would be sent to infiltrate the party and notify the Virginia Alcoholic Beverage Control Board, which helped stage a raid.

Consider what one policeman did to Retha Morgan, as other officers swarmed over the family property and still others set up a roadblock to check all cars leaving the party.

"My mother walked up to the roadblock with my aunt to see if any guests were having problems," Kurt St. Clair recalled. "A cop told her, 'I'm not on your property anymore, you're on my property. Now back off.' My aunt tapped her on the shoulder and said, 'Let's get out of here,' but the cop said, 'She's not going anywhere.' Then he started giving her sobriety tests, making her touch her nose, making her lean backward until she was almost flat on her back. But she passed.

"Then he pulls out this Breathalyzer and shoves it at her and says, 'Blow,' while he is pressing all of these buttons. Without showing the results to anybody, he says, 'You're under arrest.' Then he handcuffed her and took her to jail."

Police disbanded the roadblock after Morgan's arrest -- and even left the party although other guests remained. But the nonsense continued.

"I became so frustrated dealing with the system," Robert Morgan said. "I was treated very shabbily by the police and the magistrate when I tried to get my wife released."

Retha Morgan, charged with being drunk in public, remained in jail from about 3:45 a.m. until 7:25 a.m. Friday. She was told that she could obtain her release by paying $30, which her husband did. She says she did not know that the $30 was a fine, and that paying it was an admission of guilt.

She was described as "very distraught" yesterday.

"It's like a rape case," Robert Morgan said, "with us against the police."

Police say that they went to the Morgan home in the 10000 block of Old Hunt Road after patrol officers spotted about 50 teen-agers milling around in the neighborhood and said that some teens appeared to be drinking and others appeared to be drunk.

However, after the raid on the Morgan house, St. Clair said, he found a sheet of paper, apparently dropped by one of the undercover agents, which indicated that the party -- along with four other gatherings being held in the area that night -- had been targeted for possible infiltration even before it began.

Fairfax police say it is a longstanding practice to send plainclothes officers to parties where officials have reasonable cause to believe that the law is being broken. But according to some Fairfax residents, angered over news accounts of the Morgan arrest, these practices are arbitrary and unclear.

Even at the Morgan home, some police officers took it on themselves to mete out punishments, such as assigning some students to write 500-word essays, while other officers chose to make arrests.

In a blanket statement of approval, the commonwealth attorney's office says that what happened was within the law. But as far as many residents are concerned, it seemed like the KGB had teamed up with a hick cop shop for a gross abuse of power.