Having your life exposed on TV -- Marion Barry and Rob Lowe are only two of the stars whose private exploits have been displayed nationwide

In an era in which real-life trials play on TV as nightly courtroom dramas, and the evening news uses re-enactments to ”heighten” reality, it’s no surprise that videotape has become the star of show after show.

In the ’70s, videotape’s immediacy and simplicity made it the ideal medium for two television genres in which speedy production was essential: local news and soap operas. Now, as the two highly melodramatic forms become more alike, video is assuming an ever-stronger identity.

Videotape’s thrill is its apparent ability to catch people red-handed: ”Preppie” murderer Robert Chambers, giggling, twists the head off of a doll. Bleary, postcoital Rob Lowe leers into the camera as a girl lolls in the background. A congressman lines his pockets with cash bribes — it’s one thing to hear about it, another to see the $100 bills. But appearances can be deceiving: Not everybody who is arrested is guilty, and not everything that appears on tape is hard evidence.

In the court of public opinion, that rarely matters. When an official seems to offer a bribe or grab an envelope full of money, or looks as if he’s lifting a crack pipe to his mouth, viewers usually deliver a fast verdict. What follows on the next page is a guide to memorable videotaped highs, lows, and Lowes.

JOHN DeLOREAN Prosecutors view videotape as the high-tech equivalent of a smoking gun, but sometimes it’s pointed in the wrong direction. Weeks before auto magnate John DeLorean’s trial on drug-smuggling charges was to begin in 1983, Hustler publisher Larry Flynt obtained tapes of the bust and sold them to CBS. Huge audiences saw DeLorean handle a cocaine-filled suitcase and call it ”good as gold.” One L.A. news show aired segments over six nights, prompting doubts on whether DeLorean could get a fair trial. Eventually, a jury decided Federal agents had entrapped DeLorean, and he was acquitted.

REP. DONALD E. (BUZ) LUKENS Did Ohio Congressman ”Buz” Lukens contribute to the delinquency of a minor by having sex with a teenage girl? ”I do categorically deny (it),” he said upon his indictment on February 23, 1989. Three months later, Lukens was convicted after a secretly recorded videotape showed him offering to seek a government job for the girl’s mother, who asked him why he was ”messin’ around” with her daughter. ”I didn’t really know she was a teenager,” he replied. Constituents saw the tape for themselves on a local TV station, and Lukens lost his next election.

PATRICIA HEARST At the 1976 trial of kidnap victim-turned-bank robber Patricia Hearst, conflicting interpretations of two films were crucial to its outcome. One sequence, shot by a security camera at San Francisco’s Hibernia Bank, showed Hearst toting a carbine during a robbery. Her lawyer, F. Lee Bailey, claimed the captors were holding guns on her at the time; the prosecution disagreed. Bailey also used a tape of a Symbionese Liberation Army shootout to argue that Hearst would have endangered her life if she had tried to turn herself in. Jurors saw it differently. Hearst was convicted, and won clemency after serving 22 months of a seven-year sentence.