Subgame Perfect Plea Bargaining in Biform Judicial Contests

The judicial process is modeled as a biform contest. A sufficient condition for a non-empty core is provided, and it is shown that the effect of the severity of charges on the core is ambiguous. The practice of plea bargaining actually applies Moulin’s (1984) mechanism which non-cooperatively implements the Kalai-Smorodinsky (1975) bargain solution, implying that equilibrium plea deals are regressive. Namely, defendant’s gain and social cost from a guilty plea deal both increase with the severity of the crime. The charge reduction rate is inversely related to the defendant’s, and positively related to the prosecutor’s, “fear of ruin” index.