B ACK in September 1995, Sam Wardlow was standing on the street in a Chicago neighborhood known for its heavy drug activity when he spotted uniformed Officer Timothy Nolan driving by in his patrol car.

Up to that point, Wardlow hadn’t been doing anything unusual or suspicious. But the moment he spotted Officer Nolan, he bolted and began running down the nearest alley. Nolan and his partner, noticing Wardlow’s sudden flight, gave chase.

When they caught up with Wardlow, they found a white envelope in his pocket. Inside was a fully loaded Colt .38 revolver.

Wardlow, who had a lengthy criminal record, was convicted of unlawful use of a weapon by a felon and sentenced to two years. But his conviction was overturned by the Illinois Supreme Court – which ruled that “the sudden and unprovoked flight of a suspect upon seeing police” is “insufficient to create a reasonable suspicion of involvement in criminal activity.”

Indeed, said the court, the cops had acted on “nothing more than a hunch” when they decided to chase Wardlow (who, since his conviction was overturned, has served time on an unrelated drug charge).

The Illinois decision – which is now going to be reviewed by the U.S. Supreme Court – is just as demeaning to law-enforcement officers as was the similar 1996 ruling by Manhattan Federal Court Judge Harold Baer that invalidated a police search of a car from which four men had fled in Washington Heights.

Like Wardlow, the men were engaged in criminal activity: The car held 80 kilos of heroin and cocaine and $1 million in cash. But Baer ruled that fleeing the police in Washington Heights should not be considered suspicious – in fact, he said, such behavior is entirely reasonable in an area where “residents … tend to regard police as corrupt, abusive and violent.”

To date, the Supreme Court has never spelled out exactly what constitutes “reasonable suspicion” of criminal activity. But a certain measure of common sense should govern.

“Flight from police is such an extreme reaction that it lies outside the bounds of normal human conduct,” argued Chicago prosecutor Veronica Ximena Calderon. “Flight from police provides the strongest indication that criminal activity is afoot.”

To say otherwise – as the Illinois Supreme Court did – creates an untenable state of affairs in which police are forced to “shrug their shoulders and helplessly stand watching” while people run away from them.

Nowhere in these rulings is there any suggestion that training and street experience provide cops with more than just a “hunch” about possible criminal activity. In the wake of the Amadou Diallo case, however, police are being portrayed as a group of gun-toting vigilantes who have no more ability to recognize suspicious activity than does the average bystander.

That, at least, seems to be the underlying assumption of a bill announced last week by Reps. Henry Hyde (R-Ill.) and Jose Serrano (D-Bronx) that would launch an investigation of the adequacy of police-training policies.

At least that’s what Hyde thought he was introducing. As Serrano’s press release makes clear, his intent is to establish a national commission that will “investigate the apparent pattern of police violence against people of color in New York City” and “examine the causes of police abuse of power” – a situation, he says, that has “reached crisis proportions.”

Serrano, like Wardlow’s defenders, maintains that police don’t know what constitutes suspicious behavior. “Does the policeman know that if you stop an Amadou Diallo, for instance, … that maybe sticking your hand in your pocket doesn’t necessarily mean you have a weapon?” asks Serrano. “You could have a green card to show the police officer.”

Indeed he might. But he might also have a gun – and the cop who hesitates without at least taking the precaution of protecting himself against that possibility might find himself on the receiving end of a hail of bullets.

That leads to widespread demoralization – which is why, not surprisingly, arrests here have fallen sharply since the Diallo shooting. Sure, cops should do their job correctly – but they should be allowed to do their job. And a cop whose knowledge and experience is constantly being second-guessed by jurists who’ve never had to patrol a high-crime neighborhood can’t do his job.

In a famous 1926 opinion delivered while he was still sitting on the New York Court of Appeals, the renowned Justice Benjamin Cardozo lamented the ominous implications of excluding important evidence for such reasons: “The criminal is go free because the constable has blundered,” he wrote.

Hopefully, the Supreme Court will come to the realization that – in the case of Sam Wardlow and many others like it – the constables did not blunder.