The justices were deeply engaged, and deeply split.
It is a logical inference that they were deadlocked at 4 to 4 after the first argument on Jan. 9, and that it is now up to Justice Samuel A. Alito Jr., who took his seat later that month, to break the tie.
But that is not necessarily the case; any Supreme Court decision is a work in progress until it is issued. "I may have my mind made up, but I'm open to change," Justice Stephen G. Breyer told Timothy A. Baughman, a lawyer from the Wayne County, Mich., prosecutor's office who argued for the state.
Nonetheless, Justice Breyer proceeded to make it clear that he remained unpersuaded by Mr. Baughman's argument that the Michigan Court of Appeals was correct in refusing to exclude from Booker T. Hudson's trial the drugs the police found when they executed a search warrant by bursting into his home without knocking or waiting for him to open the apparently unlocked door.
This means of entry violated the "knock and announce" rule that modern Supreme Court precedents have made part of the current understanding of the Fourth Amendment's prohibition of unreasonable search and seizure. There was no dispute that the Detroit officers' action violated the rule. The question for the justices was what consequences should flow from the violation.
"A child of 2," Justice Breyer told the prosecutor, would know that the officers' sudden entry made it more likely that they would find the incriminating evidence. To permit evidence found in these circumstances to be admitted at trial would be "to let a computer virus loose in the Fourth Amendment," he said.
Justice Alito had no questions for Mr. Baughman, but he asked questions of the defendant's lawyer, David A. Moran, that suggested some sympathy for the state's position.
Justice Alito asked Mr. Moran to assume that the police had waited 10 seconds before entering, rather than the 3 or 4 seconds that they actually waited after they announced their presence through the closed door. The Supreme Court's precedents have suggested that 15 to 20 seconds is the appropriate delay. Would excluding the evidence "be in any way proportionate" if the police were only "slightly on the wrong side of the line?" Justice Alito asked.
Perhaps not if it was really that close, as opposed to the "flagrant violation" in this case, Mr. Moran replied. The rule that illegally seized evidence should be excluded was meant to deter the police from violating the Constitution in the first place, he said. "Is there any method of deterrence other than teaching by example?" he asked.
What about telling police officers that they will not be promoted if they violate suspects' rights, Justice Antonin Scalia wanted to know. His suggestion appeared more rhetorical than serious, serving along with a number of his other interjections to make it clear that he was on the state's side in the case, Hudson v. Michigan, No. 04-1360.
Chief Justice John G. Roberts Jr. also appeared firmly in the state's camp. He asked Mr. Moran, who is associate dean of Wayne State University Law School in Detroit, what difference it would have made had the police waited 15 or 20 seconds instead of 3 or 4 after announcing their presence.
Mr. Hudson would have left the chair where he was sitting and admitted the officers, Mr. Moran said.
Why make that assumption, the chief justice wanted to know, observing that the police found a loaded gun and crack cocaine at Mr. Hudson's seat. Would Mr. Hudson really have exclaimed, "Oh, it's the police, let's see what they want?" Chief Justice Roberts asked.
Mr. Hudson was found guilty of drug possession and was sentenced to 18 months' probation.
The federal government, entering the case on behalf of the state, argued in a brief filed by the solicitor general's office that "suppression is too high a price to pay for a particular violation when the causal link between the violation and the acquisition of evidence is weak, nonexistent, or irrelevant."
Justice David H. Souter told David B. Salmons, an assistant solicitor general, that "if we accept your argument," the knock-and-announce rule "is a dead letter" because it would so often be difficult to prove that an illegal entry led to discovery of a particular piece of evidence.
Justice Souter, whose sympathy for the defense was clear, said that requiring such a link ignored an important reason for the knock-and-announce rule: "that there is enough respect for a person's privacy to say that the police should not barge in like an invading army."