The Supreme Court today gave the prosecution a big win in Connick v. Thompson, described below in the Heritage Foundation summary:

In a 5-4 decision by Thomas, the Court held that a district attorney's office cannot be held liable under section 1983 for failure to train its prosecutors based on a single BRADY violation. 

Thompson was convicted of armed robbery, and later, capital murder.  He chose not to testify at his murder trial because of his prior robbery conviction.  A month before Thompson was to be executed, an exculpatory crime lab report was discovered relating to the armed robbery.  The execution was stayed, and his robbery conviction was overturned.  A Louisiana appellate court reversed Thompson's murder conviction, and he was acquitted when retried. 

Thompson sued the district attorney's office under section 1983, claiming they had violated BRADY by failing to disclose the crime lab report.  The equally divided Fifth Circuit court affirmed a liability finding on the theory that the violation was caused by the office's unconstitutional policy and its deliberate indifference to an obvious need to train its prosecutors on BRADY. 

In reversing the Fifth Circuit, the Court noted that a pattern of similar constitutional violations is "ordinarily necessary" to demonstrate deliberate indifference.  Thompson did not prove a pattern of BRADY violations, and mistakenly relied on the "single incident" theory of liability hypothesized in CANTON.  Deliberate indifference in this context requires proof that city policymakers disregarded the "known or obvious consequence" that a particular omission in training would cause the violation.  Here, failure to train prosecutors in their BRADY obligations did not fall under CANTON; the attorneys are trained in the law, understood constitutional limits, engage in continuing education, and must satisfy licensing and ethical obligations.  Failing to train prosecutors in the grey areas of BRADY does not amount to "a decision by the city itself to violate the constitution." 

Ginsburg filed a dissent, joined by Breyer, Sotomayor, and Kagan.  Scalia (with Alito) joined the Court's opinion but also filed a concurrence addressing the dissent.

Of course this sort of issue should never arise.  Criminal litigation is not a game.  Those who insist on putting the truth first and ending all the clever maneuvering will never have discovery issues.  When I was an AUSA, although the law and Departmental regs did not require open file discovery, I provided it in every case (except where witness safety was an issue).  It shouldn't take Brady or any office training.  It should take only the conscience that brought you into the prosecutor's office to begin with.

Defendants ordinarily have much to fear from the truth, because it tends to send them to jail.  Those on the prosecution side should welcome the truth and let the chips fall where they may.