Asymmetries and Incentives in Plea Bargaining and Evidence Production
Levmore, Saul, Porat, Ariel, The Yale Law Journal
ESSAY CONTENTS INTRODUCTION I. LIMITS ON INDUCEMENTS TO TESTIFY A. The Ban on Payment for Testimony B. Monetary Versus Nonmonetary Inducements 1. The Holdout Problem and Other Dangers 2. Holdouts and Ex Ante Payments C. Explaining the State's Asymmetrical Advantage II. PAYMENTS FOR EVIDENCE PRODUCTION A. Ex Ante and Ex Post Payments B. Regulated Payments for Physical Evidence 1. The Need for Greater Rewards 2. One Step Forward C. Distinguishing Regulated Payments for Testimony CONCLUSION
The law of evidence is full of puzzles. Many of these revolve around admissibility and, more narrowly, the rules forbidding or restricting payment to a fact witness. (1) Presumably, the dangers of self-interest and perjury are thought to dominate the benefits normally associated with remuneration for hard work. At the same time, the government--but not the defense--is able to reward witnesses in criminal cases with certain nonmonetary inducements, including agreements to seek reduced penalties, or even not to prosecute at all in both related and unrelated cases. (2) If a witness is already incarcerated, the government can offer to improve the conditions of confinement. (3) This asymmetry is something of a puzzle, for most asymmetries in criminal law favor the defendant. The asymmetry seems to disappear when physical evidence is at issue. Both prosecutors and defendants, and even potential defendants, can within limits encourage the production of physical evidence with monetary rewards, though of course pieces of evidence (like testimony) can also be judicially compelled and thus need not be purchased. (4) The ability of even interested defendants to pay for physical evidence is sensible rather than doubly puzzling if one regards the dangers of bias and false testimony as much reduced in the case of physical evidence. At the same time, this permissiveness with respect to one kind of evidence raises the question of why we do not see more payments (or requests for payment) for things like privately owned surveillance devices that could generate important evidence.
One goal of this Essay is to develop the idea that a better understanding of the particular distaste for monetary incentives and of the asymmetry in favor of the government leads to a conclusion that law could better encourage the production of evidence. Law's focus has been on the rules of evidence gathering in the investigation of crimes and accusations. We suggest that optimal crime fighting, as well as the preservation of individual rights, likely involves greater private investment in strategies that are set in motion before specific crimes are committed. Our positive theorizing about several asymmetries in inducements to produce evidence--monetary/nonmonetary, prosecution/defense, testimonial/physical--has important implications for the question of how to encourage the production of evidence and thus the accuracy of verdicts and the efficient reduction of crime. (5) In the process, we offer a number of explanations for the existing and superficially troubling asymmetries. (6)
Part I analyzes the first two asymmetries. We begin with the prohibition on monetary payments to witnesses, and note the allowances for informants who are not quite, or not yet, witnesses in court. Private parties and governments can, for instance, offer rewards for information leading to arrests, and both can establish rewards for whistleblowers. Payments that facilitate the recovery of stolen property are also permitted, though these might generate testimonial evidence. Disallowed payments should be understood in the shadow of litigants' power to compel testimony from identifiable witnesses. At the same time, monetary payments might undermine civic virtue and encourage false testimony. We suggest that none of these features is as useful an explanatory device as the idea that monetary payments would often give witnesses monopoly, or holdout, power. …