Maryland v. Garrison

Justice Blackmun wrote the dissent. Blackmun believed that the search violated the Fourth Amendment and that the evidence should have been suppressed. Regarding the search of apartments in multi-unit buildings, courts have found invalid those warrants that do not describe the targeted unit with enough specificity to prevent a search of all the units in the building. Blackmun and the court of appeals both felt that the warrant specified only the search of McWebb's apartment, not Garrison's. Therefore the search was warrantless and unreasonable and the evidence gathered in the search should have been excluded.

Blackmun noted that it might make sense to excuse a mistake that produced evidence against a person being investigated based on probable cause, but it does not follow that a mistake should be excused when evidence is collected on someone not singled out and who was the victim of an error.

Detective Marcus, who obtained the search warrant, did not make reasonable efforts to verify the layout of the third floor. He should have noted that the building had seven mailboxes, and he should have asked his informant if McWebb's was the only apartment on the third floor. Blackmun expressed doubt about whether the warrant was executed with reasonableness. Only when they were well into their search and had discovered incriminating evidence, did the police realize their "mistake." They should have realized they were in a separate apartment well before they discovered the evidence. When they first encountered Garrison, they asked him who he was, but not where he lived. The officers should have realized their error when they made their security sweep since each apartment had a bathroom, a kitchen, a living room, and a bedroom. "Even if a reasonable error on the part of police officers prevents a Fourth Amendment violation, the mistakes here, both with respect to obtaining and executing the warrant, are not reasonable and could easily have been avoided."

The decision in this case was an example of the good faith exception to the exclusionary rule. The exclusionary rule states that evidence gathered unlawfully should be excluded from a trial. Since the 1980s, the Supreme Court has established many exceptions to this rule. The majority of the Court felt that the exclusionary rule was not a personal right, but was created to deter police misconduct. Excluding evidence that the police gathered through an honest mistake would not deter misconduct and would allow a guilty person to go free. Justices Brennan and Marshall maintained that if a search warrant is faulty, the evidence should be excluded from trial, even if the problem with the warrant was due to an honest mistake. This would preserve the integrity of the Fourth Amendment.