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 bargain
Sometimes, the prosecutor agrees to reduce a charge or to drop some of multiple charges in exchange for the defendant's acceptance of the penalty. Defendant, in the request, could argue with the penalty and aggravating and extenuating circumstancing with the prosecutor, that can accept or refuse. The request could also be made by the prosecutor. The plea bargaining could be granted if the penalty that could be concretely applied is, after the reduction of one third, inferior to five-year imprisonment (so called "patteggiamento allargato", wide bargaining); When the penalty applied, after the reduction of one third, is inferior of two years imprisonment or is only a fine (so called "patteggiamento ristretto" limited bargaining), the defendant can have other advantages, like sentence suspended and the effacement of the crime if in five year of the sentence, the defendant doesn't commit a similar crime.