What the Supreme Court took away from us

'SO THAT'S IT?" My young African American client was shaking his head in disbelief, a look of expectant perplexity warming his face.

"Yep," I smiled, giving him a quick embrace, "Case dismissed."

"Cool," he said, shaking his head just a little bit.

This exchange took place some years ago in a fluorescent-lighted hallway just outside the subterranean courtroom of Judge Robert Cohen in the Bronx. The judge had just ruled that because the police illegally searched a bag inside the trunk of my client's car, the gun they found there would not be admitted into evidence. And so, there, outside Cohen's courtroom, I was saying goodbye to a client who no longer faced the specter of a prison term.

Such an outcome, though depicted regularly on "Law & Order," is actually uncommon. And from now on, there'll be even fewer.

In a complicated and contentious 5-4 decision last week, the U.S. Supreme Court ruled in Hudson vs. Michigan that even though the police had manifestly violated the long-established "knock and announce" rule when they ran into Booker Hudson's Detroit home, the evidence they illegally obtained (drugs and a firearm) could still be used against Hudson in his trial.

In his decision for the sharply divided court, Justice Antonin Scalia ruled that despite the "knock and announce" rule's long and storied history, improvements in police training and the possibility of civil lawsuits would sufficiently deter police misconduct, making the social costs of excluding the evidence outweigh the deterrent value of the sanction.

As Justice Stephen Breyer's dissent suggests, last week's ruling is itself a significant departure from traditional 4th Amendment jurisprudence. But though the Hudson decision is deeply alarming for what it says, it is even more so for what it presages: a direct attack on the entire remedy of suppression.

There is a certain majesty to the "exclusionary rule" -- the notion that the proper remedy for a procedural error is to preclude the use of tainted evidence, even if that means that a manifestly guilty person will go free. It evinces a particularly American faith in the value of process, an acute sensitivity to the importance of fairness and to the value of strict limits on how government may invade a citizen's private space.