[2] Immediately upon entering, the officers found Hudson sitting on a chair in the living room while numerous other individuals were running about the house.

In the ensuing search, the police found five rocks of crack cocaine weighing less than 25 grams (7⁄8 oz) inside Hudson's pants pockets.

At Hudson's trial for cocaine possession with intent to deliver[3] and possession of a firearm during the commission of a felony,[4] Hudson argued that—since the premature entry violated the knock-and-announce requirement and, therefore, according to the Supreme Court's decision in Wilson v. Arkansas (1995),[5] his Fourth Amendment right to be free from unreasonable searches and seizures—the exclusionary rule required that the evidence obtained in the ensuing search must be suppressed.

Following a bench trial, Hudson was convicted of possession of less than twenty-five grams of cocaine[8] and sentenced to probation for eighteen months.

After discussing those decisions, Scalia wrote: [E]xclusion may not be premised on the mere fact that a constitutional violation was a 'but-for' cause of obtaining evidence.

The majority opinion goes on to note that the costs of exclusion for knock and announce violations outweigh the benefits of admitting the evidence.

Breyer began his dissent with a rebuke of the majority opinion: In Wilson v. Arkansas, 514 U. S. 927 (1995), a unanimous Court held that the Fourth Amendment normally requires law enforcement officers to knock and announce their presence before entering a dwelling.

Breyer wrote that the strongest argument for application of the exclusionary rule to knock-and-announce violations is that it serves as a strong deterrent to unlawful government behavior.

They emphasize the need to assure that its constitutional protections are effective, lest the Amendment "sound the word of promise to the ear but break it to the hope.

It has not done so.Justice Antonin Scalia was accused of twisting the arguments made by Samuel Walker in Taming the System: The Control of Discretion in American Criminal Justice.

Scalia, in support of weakening the exclusionary rule, presented from Taming the System that there has been tremendous progress "in the education, training and supervision of police officers" since Mapp v. Ohio in 1961.