Israeli courts discriminate against Israeli Arabs. If there had been any doubt left about this, a comprehensive, first-of-its-kind study commissioned by Israel's Courts Administration and the Israel Bar Association just determined it decisively.

According to the study, whose main findings were reported by Tomer Zarchin in yesterday's Haaretz, Arabs are given jail sentences more often than Jews convicted of the same offenses, and Arabs receive longer sentences than Jews who are jailed. The study's authors conclude that their most conspicuous finding is the tendency of Israeli courts to treat Arab defendants more harshly: When Arabs wind up in court, they are more likely to be convicted; when convicted, they are likely to receive a stiffer sentence than a Jew normally would. It's hard to imagine a more disturbing fact.

This is no longer just a matter of discrimination on the basis of national identity by small communities' admissions committees or by bouncers at nightclubs. This isn't just a matter of budgetary discrimination. This worrisome paroxysm has already reached its pinnacle: the court system itself, which is supposed to serve as society's beacon of law and justice.

The Courts Administration and the Bar Association did well to commission the study. But now, it is incumbent upon the court system to eradicate this plague of systematic discrimination.

Israel's judges dwell among their people, but they must not allow themselves to become infected by the racist mood that is spreading through Israeli society. On the contrary, the court system must battle against this morally reprehensible attitude.

Arab citizens must have equal rights in every regard - but first and foremost when dealing with the law enforcement system. They must know they will never face discriminatory sentencing because of their national identity. This essential condition, however, is not currently being met.

Every level of the court system, from the Supreme Court down, must designate this as one of its most pressing and important missions - to grant equal treatment to all who appear before it. Supreme Court President Dorit Beinisch must send an urgent and unequivocal message to every judge in Israel: Sentencing discrimination against Arabs must end. Racism? Not in the courts.

Because otherwise, those who accuse Israel of maintaining an apartheid regime will be justified with regard to Israel's own Arab citizens.