That comment came in a story about a mistaken raid in which Mario Paz, an innocent man, was shot dead by a raiding SWAT team when he mistook them for criminal intruders and reached for a gun to defend himself.
Common sense says the El Monte official is unusual only in his forthrightness. Kraska's research shows that in most cities that have a SWAT team, the SWAT team serves the vast majority of drug warrants. The whole justification for SWAT procedures, which include serving warrants in the wee hours of the night and shock tactics like "flash bang" grenades, black masks, and overpowering weaponry, are to take a suspect by surprise. Were SWAT teams carefully observing the spirit of the announcement requirement by giving a vigorous knock, a full-throated announcement, and appropriate time for an occupant to answer, they'd be defeating the purpose of using paramilitary tactics to serve search warrants in the first place.
Since Wilson, the Supreme Court has only muddied the issue.
In the 1997 case Richards v. Wisconsin, the court appeared to be veering toward more protection for defendants, ruling Wisconsin's practice of serving all drug warrants with no-knock raids to be unconstitutional. Writing for the majority, Justice John Paul Stevens laid out a clear, eloquent defense of the Castle Doctrine: "The common law recognized that individuals should be provided the opportunity to comply with the law and to avoid the destruction of property occasioned by a forcible entry. ... These interests are not inconsequential."
But six years later, the court abandoned just that principle and adopted an entirely different standard. In U.S. v. Banks, the justices unanimously ruled that 15 to 20 seconds was an adequate wait time between police announcement and forced entry. More significant than the court's actual ruling, however, was its reasoning, summarized by Justice Souter rather concisely:
On the record here, what matters is the opportunity to get rid of cocaine, which a prudent dealer will keep near a commode or kitchen sink. …
[I]t is imminent disposal, not travel time to the entrance, that governs when the police may reasonably enter.
With those two clauses, Souter effectively dismissed the common-law principle that announcement protects the innocent from an unjustified home invasion and instead instructed police to treat everyone named in a drug search warrant as if they were already guilty. What good is an announcement if police aren't required to give you sufficient time to answer the door? Under Souter's reasoning, it's difficult to understand what purpose the announcement requirement put forth in Wilson serves at all, other than offering a quaint, ceremonial homage to a time when the Fourth Amendment was more than a mere formality.
The Hudson case the court is now considering deals with illegal no-knock raids. That is, raids in which police couldn't even manage to follow the almost-perfunctory hoops they're required to jump through to get a legitimate no-knock warrant.
In Hudson, police in Michigan knocked and announced themselves, but waited just 3 to 5 seconds before breaking into the home of Booker T. Hudson. Once inside, they found a substantial amount of cocaine and charged Hudson with various drug crimes. When a trial court found the wait time insufficient to satisfy the knock-and-announce requirement, Hudson moved to have the evidence suppressed.
The case eventually reached the Michigan Supreme Court, which ruled that suppressing the evidence seized in the raid wasn't a proper remedy for police violating the knock-and-announce rule, and cited the inevitable discovery doctrine: Because police had an otherwise valid search warrant, their failure to announce was inconsequential. They would have found the drugs anyway.
But the exclusionary rule's primary purpose is to serve as a deterrent against Fourth Amendment violations. If police know that breaking a particular Fourth Amendment protection will result in the suppression of any evidence they find, there's strong incentive for them to follow the law.