Plea bargaining in the United States
The constitutionality of plea bargaining was established by "Brady v. United States" in 1970, although the Supreme Court warned that plea incentives which were sufficiently large or coercive as to over-rule defendants' abilities to act freely, or used in a manner giving rise to a significant number of innocent people pleading guilty, might be prohibited or lead to concerns over constitutionality. "Santobello v. New York" added that when plea bargains are broken, legal remedies exist.
Plea bargaining in the United States
The shadow-of-trial argument asserts that in the aggregate, plea agreements merely reflect the outcome that would have transpired had the case gone to trial. For example, if the accused faces 10 years and has a 50% chance of losing in court, then an agreement will result in a five-year sentence, less some amount deducted for saving the government the cost of trial. Theoretically, the shadow-of-trial should work even better in criminal cases than in civil cases, because civil judgments are discretionary, while criminal judgments are often regulated by mandatory minima and sentencing guidelines, making sentences more predictable.