By a ideologically right-left, 5-4 vote, the U.S. Supreme Court ruled today (PDF) that a wrongly convicted Louisiana man—who at one point was just weeks away from execution—isn't permitted to sue the DA's office that for 14 years sat on the evidence proving his innocence.

Jacob Sullum wrote about Connick v. Thompson in March of last year. As Sullum pointed out, while it's clear that prosecutors knew about the evidence for years (a bloody piece of cloth), there are competing theories about whether they knew they had to turn the cloth over and willfully withheld it anyway, or if they simply didn't know they were obligated to turn it over. (As Sullum also noted, it's hard to decide which scenario is worse.) The latter seems rather unlikely, even though during the civil trial, Orelans Parish District Attorney Harry Connick and his assistants apparently couldn't articulate the Brady Rule, the law requiring the disclosure of such evidence. Of course, the former—the willful misconduct—is also much harder to prove.

In any case, the Court's ruling today, taken with past rulings, further illustrates how the old mantra that "ignorance of the law is no excuse" seems to apply to everyone except for actual members of law enforcement.

The majority opinion, written by Justice Clarence Thomas, found that the failure of Connick (fun side note: he's the father of crooner Harry Connick, Jr.) to train his assistants on their obligation to turn over exculpatory evidence isn't negligent enough to subject the government that employs him to liability. Connick and his assistants themselves (an office with a long history of misconduct) were already protected from any personal liability by absolute prosecutorial immunity, a concept the Supreme Court essentially invented from whole cloth.

Keith Findley, President of the Innocence Network, comments:

"Basically, what the Court is saying is that because they are lawyers, there was no reason for the District Attorney to believe that his prosecutors might need training to be sure they are fulfilling their constitutional obligations to disclose information that might be useful to their defense. This logic completely ignores the reality of what happened to John Thompson who was sentenced to death by prosecutors who repeatedly failed in their obligation to disclose exculpatory information. No other profession is shielded from this complete lack of accountability."

The ruling also negates a $14 million jury award to John Thompson, the man wrongly convicted. It also means that for his 18 years in prison, 14 of which he spent on death row, Thompson will now at most get $150,000, the maximum compensation for a wrongful conviction allowed under Louisiana law.