Mayor Bloomberg’s decision, in the midst of the crisis over the shooting of Sean Bell, to turn to the Reverend Al Sharpton is one of those errors that he is going to have to deal with as he contemplates a campaign for the presidency in 2008. New York City itself will no doubt survive the mayor’s faux pas, because the fact is that police shootings in this city are among the lowest per capita of any big city. And the idea that the leadership of the police department is somehow racist, or even indifferent to the sensitivities of the minority communities in this city, is going to be hard even for the critics of the police to credit. But the mayor’s reputation as a leader in a crisis, that is something that takes a long time to earn — and the mayor has had a good run of it — but that can be damaged in a matter of hours.

We have no doubt that the mayor’s reputation suffered Monday. Certainly thousands of New Yorkers shook their heads in amazement yesterday when they picked up their newspapers to see the pictures of the mayor embracing Rev. Sharpton. Amazement turned to dismay as the mayor promptly pronounced the firing of 50 shots by the police “excessive” and “unacceptable.” It may well be that something went wrong, that the police erred. But it was precisely the mayor’s responsibility at that moment to stress the need for avoiding the pronouncement of judgments. If he can be rushed into a premature pronouncement by the likes of Rev. Sharpton, how would he perform in a showdown with the likes of, say, Presidents Putin or Hu.

“So much for withholding judgment before all the facts are in,” is how the president of the Detectives Endowment Association, Michael Palladino, characterized, to our Bradley Hope, the mayor’s error. He said he thinks the mayor’s comments “unfairly taint the entire situation. “The mayor wouldn’t have had to be thinking far back into our recent history to appreciate the need for caution. A jury acquitted police of any criminal misconduct in using 41 shots against Amadou Diallo in the Bronx, which was, arguably, much less frightening a situation to the police than what happened over the weekend in Queens. In this case, police were confronting an adversary who, unlike Diallo, was in a car, and, also unlike Diallo, was accompanied by at least two and possibly three other persons.

Moreover, the New York Post reports that all three of the men the police confronted had arrest records; Bell twice for drugs and once for a gun, another man for armed robbery, and a third for gun possession and robbery. Mr. Bloomberg has been on a campaign against gun violence lately. He has pursued it by convening press events in Atlanta and Boston with other mayors, speaking to the Centers for Disease Control and Prevention, and dispatching private investigators outside New York to gather evidence to be used in civil lawsuits against gun dealers. All that may or may not help, but what experience shows actually does help reduce illegal gun violence is aggressive police work. That doesn’t mean sending police out to shoot suspects without a trial, but it does mean backing up the police until all the facts are in.

As the officers in this case certainly deserve. The detective who reportedly fired 31 shots in Queens had also reportedly not fired his weapon in the line of duty, other than on a firing range, in 12 years. Plenty of questions are unanswered. Was there a fourth person who escaped with a gun? What do toxicology reports show about how much Bell had to drink before he got behind the wheel of a car? How about the reports that one of the men police shot had made reference earlier to returning to his car to get a gun? What does it do to police morale when the mayor rushes to judge detectives who may have made a mistake once in 12 years or who may have been correctly defending their lives from attack? It sends a message to the rest of the police force — you are better off signing up for a desk job or hanging out at a Dunkin’ Donuts than trying to risk getting in the line of fire.

Having said all this, we’re also of the mind to say that Mr. Bloomberg has been a fair, calm, and prudent leader. He hired and backed a great police commissioner. So the mayor is entitled to his own mistakes. The big one he has made here is more political than anything else. “Sharpton’s stature elevated to new heights,” is the way the Associated Press headlined a dispatch yesterday about the red-carpet treatment that the reverend got at City Hall. That’s the same Rev. Sharpton who threw himself into opposing the campaign for the Senate of the same Joseph Lieberman that Mr. Bloomberg was supporting. Rev. Sharpton’s candidate, Ned Lamont, got trounced. As Fred Siegel of Cooper Union pointed out to us yesterday, “As Ned Lamont made clear, having Sharpton close to you is not an asset.”