Shields, Swords, and Fulfilling the Exclusionary Rule's Deterrent Function
Kainen, James L., American Criminal Law Review
INTRODUCTION I. THE FLIGHT OF THE EXCLUSIONARY RULE II. ACCURATE FACTFINDING AND SUPPRESSED EVIDENCE A. Opening the Door to Suppressed Evidence B. Contradicted Inferences or Proof C. The Inference That Suppressed Evidence Does Not Exist D. When Defendants Waive Protection Against Suppressed Proof III. THE INTEGRITY OF THE TRIAL PROCESS AND ETHICAL RULES CONCLUSION
When the exclusionary rule prevents the prosecution from using evidence necessary to bring a case to trial, the rule deters illegality while raising no issue about how it might interfere with usual factfinding processes. However, when a case proceeds to trial although a court has suppressed some prosecution evidence, courts need to decide the extent to which the defendant may benefit from the absence of the proof without opening the door to its admission. The exclusion of any relevant evidence raises similar questions, and courts often say the exclusionary rule is a shield from suppressed evidence, but not a sword with which the defendant can inflict damage on the prosecution's remaining case. (1) Nonetheless, this Article argues courts err when they analyze whether the defendant "opened the door" to suppressed evidence with a metaphor appropriate for rules excluding evidence for different--and less weighty--reasons than encouraging respect for individual constitutional rights. Employing usual evidentiary tests for opening the door unduly diminishes the effectiveness of exclusion as a deterrent of police misconduct when investigators expect the potential evidentiary payoff will not be necessary to bring the case to trial, but will nonetheless be useful to obtain a conviction.
Whether the defendant has opened the door to suppressed evidence is a related, though distinct question from what the boundaries of the exclusionary rule should be. The Supreme Court has defined the scope of the exclusionary rule to the extent of holding suppressed evidence can be used to impeach a testifying defendant, but not to establish the prosecution's case-in-chief or to impeach other defense witnesses. (2) Besides the direct questions of scope are questions about how defendants may exploit the absence of suppressed evidence before a court will hold that the defendant opened the door to its admission. This Article criticizes recent decisions finding a defendant opens the door to suppressed evidence merely by highlighting the absence of that evidence or by offering other evidence to which the suppressed proof is relevant rebuttal. (3) It argues those decisions erroneously assume relevance, probative value, and unfair prejudice are the only factors that should influence this decision. While this is true enough for evidence originally excluded to promote accurate factfinding, it is not true for evidence excluded to promote other policy objectives or to respect other principles.
Whether and how a party can take advantage of the exclusion of suppressed evidence is a question whose answer depends upon a contextual analysis of how "opening the door" decisions affect the deterrence promoted by exclusion in the first instance, not upon whether they divert the factfinder in its quest for truth. Thus, courts contravene the prohibition against impeaching defense witnesses when they invoke Rule 403 of the Federal Rules of Evidence to preclude the defendant from admitting evidence that contradicts suppressed proof, because preclusion has the same effect as rebuttal. Similarly, courts improperly extend the prosecution's use of illegally-obtained evidence when they allow it to discourage counsel from arguing inferences the suppressed proof contradicts by permitting its admission if he does. In either case, the prosecution quickly learns obtaining evidence illegally has a payoff in excess of that contemplated by the Supreme Court. Prosecutors routinely find the suppressed evidence useful to deter or rebut defenses even when not introduced in the prosecution's case-in-chief or to impeach a testifying defendant. …