Public Security Minister Yitzhak Aharonovitch justifiably praised the police on Friday for preventing a drastic escalation of violence surrounding that day's prayers on the Temple Mount. Since tensions were acute amid several Palestinian and Israeli-Arab leaders' spurious claims of new Israeli plots against the Aksa Mosque, the minister could fairly commend the police's "honorable achievement" in maintaining relative, if not total, calm. Aharonovitch was on much less firm ground, however, in urging that we "don't blame the police" for the fatal fight outside the Van Gogh nightclub in the city center the previous night, in which 20-year-old Yitzhak Mor had his throat cut and a second man was stabbed in the back. Anyone with more than passing knowledge of the atmosphere in central Jerusalem will be aware that the heart of our capital city is rapidly becoming a late night no-go zone. Clusters of violent youth rule and roam the streets, armed with knives and with the beer and vodka bottles they've emptied, picking fights with unsuspecting victims. Of course, the police are not solely to blame for the deepening climate of intimidation and violence. As Aharonovitch and Israel Police Insp.-Gen. Dudi Cohen have frequently observed, ours is becoming an increasingly violent society, more and more kids are now carrying knives, and the response needs to be found, at least in part, in better parenting and better educational values. But it also needs to be found in more effective policing, and more deterrent punishment for offenders. Police are hardly encouraged to tackle the knife-wielding gangs when judges routinely let off offenders with what amounts to a rap on the knuckles. But the reality is that, in acute contrast to the creditable policing of Friday's prayers and attendant tensions, the policing of the late-night bar and nightclub areas of central Jerusalem is demonstrably failing to deter violence. The Van Gogh nightclub is located on Koresh Street, which also happens to feature a police office and which is situated around the corner from the main police headquarters in the Russian Compound. Such proximity to the forces of law and order, however, clearly did not dissuade people from bringing their blades out dancing with them on Thursday night. And when two young women had an argument on the Van Gogh dance floor and the dispute turned violent outside, those knives were drawn with fatal consequence. Youngsters who have spent time in the downtown area in recent weeks can tell numerous stories of punch-ups and beatings, of bottles smashed on people's heads, of knives drawn - incidents in which blood was spilled, incidents that could easily have led to the same kind of fatal result. And they can also tell of chases through the streets, of the desperate search for a protective police presence, and of apparent police indifference when it comes to trying to track down offenders. Fights are common in the very area, ironically, where the Wiesenthal Center is building its Museum of Tolerance. In one recent incident near there, a youngster was set upon by a gang of youths who smashed him on the head with a bottle, then kicked and punched him on the ground. When a friend tried to intervene, they turned on him and chased him through the streets. The victims found their way to a police patrol unit - who called an ambulance for the youngster bleeding from the head but, according to those who were there, made no effort to track down the assailants. Youths say they know who many of the regular offenders are, but are terrified to identify them to the police because they fear that the courts will impose trifling punishments, if any, and that the offenders will then turn on those who identified them. When national leaders pay attention to violent lawlessness in Jerusalem, it is usually with regard to the conflict with the Palestinians. Plainly, and sensibly, that's where the police placed its emphasis last weekend. But while the force did a good job safeguarding the Old City and east Jerusalem on Friday, it can't go on ignoring the climate that, almost inevitably, saw a violent killing in what ought to be a trouble-free downtown the night before.