In the case of Florida v. Wells in 1989, the U.S. Supreme Court ruled on a matter concerning jury instructions during death penalty cases. The defendant, Johnny Calvin Wells Jr., was convicted for first-degree murder and robbery in Florida state court and sentenced to death by electrocution. During his trial, the judge instructed the jury that they could recommend a sentence of life imprisonment or death based on their consideration of certain aggravating and mitigating circumstances but did not provide any guidance as to how these factors should be weighed against each other. Wells appealed his conviction arguing that this lack of instruction violated his Eighth Amendment rights under the Constitution which prohibits cruel and unusual punishment. He contended that without clear guidelines jurors might arbitrarily impose capital punishment. The Supreme Court agreed with Wells' argument stating that when recommending sentences in capital cases juries must be clearly guided so as to minimize risk of arbitrary sentencing decisions; thus it held Florida's standard jury instructions were unconstitutional because they failed to guide juror discretion adequately.

In the dissenting opinion for Florida v. Wells, Justice Blackmun argued that the majority's decision was too restrictive and failed to consider important nuances of police work. He contended that it is unrealistic to expect law enforcement officers to have written policies for every possible situation they might encounter during a traffic stop or arrest. Furthermore, he believed that requiring such specific guidelines could potentially hinder effective policing by limiting an officer’s ability to use their discretion in unpredictable situations. In his view, as long as an officer's actions are reasonable under the Fourth Amendment—which prohibits unreasonable searches and seizures—they should be allowed even without a detailed departmental policy supporting them.