Knock-and-announce is part and parcel of serving a warrant. Without that, the entry into the home becomes an unlawful entry and any evidence seized becomes tainted, from that unlawful entry, and is suppressed.
At least since Weeks (1914) at the federal level and Mapp (1961) at the state level, that has been the law until now. In fact, Justice Breyer lists 41 major 4th amendment cases to document this. And what does the majority list? 4 cases, selectively reviewed and taken out of context. A context that Breyer put back in!
Since the signing of the Magna Carta, knock and announce has been the common law. Semayne's Case (1603), the Court of King's Bench explained, "the law [...] abhors the destruction or breaking of any house (which is for the habitation and safety of man) by which great damage and inconvenience might ensue to the party, when no default is in him." So it appears that part of the reason for knock-and-announce is for the prevention of destruction of private property! Researching this further reveals that the sanctity of the home and hearth were such, that the King's men would knock, announce themselves, their purpose and their authority. They were permitted entry if denied and upon warrant of the King, if no one was at home.
If there is no remedy for police/prosecutorial abuse, then what is to prevent the abuse? The exclusion of evidence is the only deterrent that works. This was pointed out in Mapp. Criminal and civil remedies did not work then, and they don't work now.
And to clear things up, at the trial court, the police said they announced, waited a few seconds and went in. The defense insisted there was no knock and no announcement. What was never contested was that the entry was unlawful. Should have been a slam-dunk. Unlawful entry results in an unlawful search. That's what the law was up till now.
What the State is saying is that IF the entry had been lawful, then the search would have been also. Irrelevent! Would have, could have, If, Might have, all mean nothing. It is what actually happened, that matters... Well, used to matter.