BOOK REVIEW : Justice in a Blindfold --and a Dunce Cap : PRESUMED GUILTY: When Innocent People Are Wrongly Convicted <i> by Martin Yant</i> ; Prometheus Books $22.95, 222 pages

What would have happened to Rodney King, we might wonder, if his beating at the hands of the police had not been witnessed and recorded on videotape?

One grim but plausible answer is suggested by the harrowing revelations in “Presumed Guilty,” a newspaperman’s study of what can go wrong inside our criminal justice system. King probably would have ended up behind bars, for some of the same reasons why countless other innocent people go to prison.

According to author Martin Yant, “several thousand Americans”--perhaps as many as 7,500--are convicted annually of crimes they did not commit. He says that as many as 350 people were wrongly convicted of crimes punishable by death between 1950 and 1985 and that “23 were executed.”

The unfortunate souls who end up in jail on a bum rap, we see in Yant’s parade of horribles, tend to be victims of bad timing or sometimes just bad luck. They are the wrong age or race, they are found in the wrong place at the wrong time, they are unsophisticated and inarticulate, they are fingered by unscrupulous jailhouse informers or perjuring witnesses, they are tormented and intimidated into making false confessions, they are represented by overworked, jaded or plainly incompetent lawyers.

Some innocents are ensnared by faulty lie detector tests or inaccurate data in police computers or the fanciful testimony of witnesses under hypnosis or overenthusiastic “expert” testimony or flawed laboratory work. At least three recent murder cases in Los Angeles County, according to Yant’s research, were shown to be flawed by false results in the testing of weapons by police firearms experts.

“Justice is supposed to be blind,” Yant cracks, “but not dumb.”

What the criminal justice system is supposed to be is self-correcting--it’s the job of the trial courts to correct the mistakes of police, prosecutors, witnesses and experts, and it is the job of the appellate courts to correct the mistakes of trial courts--but Yant makes the point that, all too often, the task of vindicating the innocent falls to the media.

Yant reports on the recent documentary film (“The Thin Blue Line”) that led to the release of Randall Young after he had served more than 12 years under a death sentence on a murder rap. A “60 Minutes” episode opened the cell door for Joyce Ann Brown, “whose only crime was having the same name as a woman who leased the car used in the robbery of a fur store.” And Peter Reilly, a high school kid accused of murdering his mother, enlisted the assistance of such celebrities as Arthur Miller, William Styron, Dustin Hoffman and Elizabeth Taylor. (She dropped Reilly a note of encouragement: “Hang in there, baby.”)

To flesh out his book, Yant looks at historical cases (Leo Frank, Sacco and Vanzetti, the Scottsboro Boys). He argues in passing that “the most egregious and unjust wrongful conviction of the century” was the case of the Lindbergh kidnaper, Bruno Richard Hauptmann. And he tells the tale of at least one condemned man who was saved only two days before his execution date by Erle Stanley Gardner’s once-famous “Court of Last Resort,” a panel of experts sponsored by Argosy magazine.

“Presumed Guilty” is hardly a scholarly or even an investigative work--most of Yant’s sources are contemporary newspaper articles. And he does not delve deeply into some of the more complex questions that he raises about the workings of the criminal courts.

The revelations in “Presumed Guilty” should not surprise us. No industry as vast and overburdened as the U.S. criminal justice system will ever achieve the cherished ideal of “zero-defect.” And we may wonder if the system makes quite as many mistakes as Yant suggests. Still, Yant performs a useful function in reminding us that each failure of the criminal justice system is more than a statistic--it is a shattered human life.

Next: Richard Eder reviews “On Giving Birth to One’s Own Mother” by Jay Cantor (Alfred A. Knopf).