Exceptions to the Exclusionary Rule

Why exceptions exist

The Supreme Court treats the exclusionary rule as a remedy meant to deter police misconduct, not as a personal right. In Herring v. United States (2009) it put the test this way: “To trigger the exclusionary rule, police conduct must be sufficiently deliberate that exclusion can meaningfully deter it, and sufficiently culpable that such deterrence is worth the price paid by the justice system.” Each exception below reflects a judgment that exclusion wouldn’t serve that purpose in a particular situation.

Good faith: warrants, databases and precedent

Warrants. In United States v. Leon (1984), the Court held that evidence obtained by officers acting in objectively reasonable reliance on a warrant later found invalid need not be excluded. It listed four situations where that reliance isn’t reasonable and suppression remains available:

• the affidavit contained information the affiant knew was false, or would have known was false except for reckless disregard of the truth;
• the issuing judge “wholly abandoned” the neutral and detached judicial role;
• the affidavit was “so lacking in indicia of probable cause” that belief in it was entirely unreasonable; or
• the warrant was so facially deficient, for example in describing what could be searched, that officers couldn’t reasonably presume it valid.

Database errors. In Arizona v. Evans (1995), a patrol car’s computer showed an outstanding misdemeanor warrant that had already been quashed. The Court held the exclusionary rule doesn’t require suppression where the error came from “clerical errors of court employees.” Herring extended that to a police database. A warrant had been recalled five months earlier, but the recall never made it into a sheriff’s database. The Court held that when police mistakes are “the result of isolated negligence attenuated from the search, rather than systemic error or reckless disregard of constitutional requirements,” the exclusionary rule doesn’t apply. It added that the rule can still reach “recurring or systemic negligence.” Four Justices dissented.

Precedent. In Davis v. United States (2011), the Court held that “searches conducted in objectively reasonable reliance on binding appellate precedent are not subject to the exclusionary rule,” even if that precedent is later overruled.

Independent source

If evidence first discovered unlawfully is later obtained through a lawful source that is genuinely independent, it can be admitted. In Murray v. United States (1988), agents entered a warehouse illegally and later searched it under a warrant. The Court said the question is whether the warrant search was “in fact a genuinely independent source.” It wouldn’t be if the decision to seek the warrant was prompted by what agents saw during the illegal entry, or if information from that entry affected the judge’s decision to issue it.

Inevitable discovery

In Nix v. Williams (1984), the Court held that if the prosecution can establish “by a preponderance of the evidence” that the information ultimately or inevitably would have been discovered by lawful means, the evidence should be received. There, an organized volunteer search would have found the victim’s body. The prosecution doesn’t have to prove the absence of bad faith.

Attenuation

Evidence can also be admitted if its connection to the violation is too remote. Brown v. Illinois (1975) identified the factors courts weigh: the “temporal proximity” of the violation and the discovery, “the presence of intervening circumstances,” and “particularly, the purpose and flagrancy of the official misconduct.”

In Utah v. Strieff (2016), an officer stopped a man without adequate suspicion, ran his name, learned of an outstanding traffic warrant, arrested him and found drugs. The Court held that discovering a valid, pre-existing warrant was an intervening circumstance that broke the chain. It noted the stop was not “part of any systemic or recurrent police misconduct.” Justices Sotomayor and Kagan wrote dissents.

The broader rules for derivative evidence are covered in fruit of the poisonous tree.

How the exceptions can come up in ALPR cases

None of these cases involved a license plate reader. How courts apply them to ALPR facts depends on the case. Some connections a defense attorney may consider:

• Stale hotlist entries. An alert on a car that had already been recovered resembles the database errors in Evans and Herring. Under Herring, whether suppression is available can turn on whether the error was isolated or reflected recurring or systemic problems. That makes records of how the list was maintained potentially relevant. See hotlists and alerts.
• Changing law. Courts are still deciding whether searching ALPR history is a Fourth Amendment search. Under Davis, a search made in reasonable reliance on binding precedent may not lead to suppression even if that precedent changes. Where no binding precedent existed, courts have to decide how the good-faith exception applies.
• Warrants based on ALPR data. Leon generally protects searches under a warrant, but not one obtained with knowingly or recklessly false statements, such as overstating what a camera read showed.
• Stops that turn up a warrant. Under Strieff, if an unlawful stop leads to discovery of a valid, pre-existing arrest warrant, evidence found in a lawful search incident to that arrest may be admitted.

State law

These are federal constitutional rules. States can provide broader remedies under their own constitutions or statutes, and courts don’t all apply the exceptions the same way. We cover state law jurisdiction by jurisdiction once it’s verified. See license plate reader laws by state.