It's the stuff of a television crime drama: Prosecutors withhold blood evidence that would exonerate the defendant in an attempted armed robbery case. The defendant is then convicted of an unrelated murder after a trial at which he dared not testify lest his previous robbery conviction be mentioned. After 14 years on death row, his execution is imminent. At the last minute, evidence clearing the defendant of the robbery attempt is produced. Later he is tried again for the murder and acquitted.
This actually happened and, not surprisingly, the longtime prisoner, John Thompson, wanted redress. He sued the office of Harry Connick Sr., at the time the district attorney in New Orleans, under a civil rights law allowing damages for the deprivation of constitutional rights. At trial, Thompson received $14 million plus lawyers' fees. But the Supreme Court last week overturned that award, writing an unhappy and unjust ending to Thompson's dramatic story.
Under the Supreme Court precedent of Brady vs. Maryland, prosecutors are obliged to give the defense information favorable to their clients. In Thompson's attempted robbery case, the prosecution possessed the report of a blood test performed on the trousers of one of the victims. It showed the blood as Type B; Thompson's is Type O. But the report wasn't turned over.