The Rap Sheet: Nolo's Criminal Law Blog

Police officers search a suspect's computer pursuant to a search warrant authorizing them to look for evidence relating to threats that the suspect allegedly made against a school.  While searching computer files, the officers come across files containing illegal child pornography.  Can the officers "seize" these files and legitimately charge the suspect for possessing child pornography?  Yes, ruled a federal court in United States v. Williams (2010).

Judges frequently have to grapple with how to adapt rules to scenarios that didn't exist when the rules were created.  Search warrants are supposed to describe carefully where police officers can search for the evidence described in a warrant.  But if a computer is the site for a search, police officers may uncover a vast amount of private and personal information about suspects and other people and groups that have nothing to do with the evidence described in a warrant. 

In the Williams case, the court ruled in favor of the police by applying an existing rule (the "plain view" exception to the warrant requirement) to a technology that didn't exist when the rule was created.  The court stated that the police officers seized the child pornography legally because it came into "plain view" as they opened electronic files that might have contained evidence of threats.

The Williams case is a reminder that legal rules have to be somewhat abstract and elastic if we expect judges to apply them in contexts that develop after the rules are created.   

The Exclusionary Rule has been controversial ever since the US Supreme Court enshrined it in the law of search and seizure in the case of Mapp v Ohio in 1961.  The Mapp doctrine is that any evidence that police officers seize in violation of the 4^th Amendment is inadmissible at

trial.  For example, assume that police officers conduct a warrantless search of a house in circumstances where they should first have obtained a search warrant from a judge.  Whatever the search turns up- illegal drugs, evidence of a past crime, etc. - would have to be excluded.  If the prosecution does not have enough independent evidence of a defendant's guilt, excluding the illegally seized evidence would result in dismissal of criminal charges.

          According to Mapp, the exclusionary rule deters police officers from conducting illegal searches.  If police officers know that illegally-seized evidence can't be used in court, they won't conduct illegal searches.   But attackers of the exclusionary rule argue that it makes no sense to "let guilty people go free because the constable has erred."

          In recent years, the Supreme Court has reduced the reach of the exclusionary rule.  For example, evidence that a police officer seizes in good faith reliance on a defective search warrant is admissible in evidence.  Nevertheless, proposals to eliminate the exclusionary rule continue to be put forward.

          A 2010 essay by law professors Samuel Estreicher and Daniel Weick published in the Missouri Law Review suggests that law enforcement agencies that establish rules and policies to deter improper searches should be exempt from the exclusionary rule.  They argue that illegal searches can be deterred without freeing guilty criminals if police agencies establish rigorous polices and training programs and discipline police officers who carry out illegal searches.

          Whether or not states and courts accept Estreicher and Weick's proposal, the debate over the wisdom of the Exclusionary Rule is likely to continue in the years to come.