Today, nearly 97% of all federal convictions are the result of plea bargaining.[1] When entering into a deal, defendants trade some of their constitutional trial rights for certainty. What motivates prosecutors is the ability to have the freedom to bargain with defendants and avoid going to trial. In doing this, the prosecutor has equal bargaining power with the defendant. At this point, the prosecutor has yet to build a case and the defendant has the opportunity to get a lighter sentence.
In Brady v. Maryland,[2] the Supreme Court held that, during a trial, the prosecution could not suppress evidence favorable to the defendant, regardless of whether doing so is in good or bad faith. The purpose of Brady is to allow defendants the right to a fair trial. Allowing defendants to see exculpatory evidence against them gives those defendants a better opportunity to adequately prepare for trial. Denying a defendant this evidence at trial is a violation of their due process rights under the Fourteenth Amendment.
Read the blog post by Tom Kelley here.
[1] See Gary Fields & John R. Emshwiller, Federal Guilty Pleas Soar as Bargains Trump Trials, Wall Street J. (Sept. 23, 2012), https://www.wsj.com/articles/SB10000872396390443589304577637610097206808 [https://perma.cc/3ZKC-47GF] (noting statistics of plea bargaining).
[2] 373 U.S. 83 (1963).