In late July, thousands of people converged on Philadelphia to disrupt the Republican National Convention and protest the corporate-controlled policies of the major political parties. Hundreds were arrested on August 1, a day on which demonstrators blocked streets, staged rallies and engaged in other acts of civil disobedience. Participants and independent media reported widespread brutality by police officers, who arrested more than 400 individuals. The most publicized case -- police infiltration of the "puppet warehouse" at 4100 Haverford Avenue -- has remained a major story in local newspapers. None of this came as a surprise to those familiar with police behavior in general, certainly not to veterans of recent protests in Seattle and Washington. But not many expected that the most vocal defender of the Philadelphia Police Department would turn out to be an African-American former civil rights activist known for his fearsome temper toward the media and political rivals. That's right. I'm talking about Mayor John Street. For those not familiar with Street's political record, think back to the heated mayoral campaign of just a year ago. During the Democratic primary, Street rival Marty Weinberg ran a commercial consisting solely of 18-year-old footage of a young, Afro-sporting and very angry Street shoving a reporter to the ground in City Hall. In his unsuccessful quest for the nomination, Weinberg appealed -- and not very subtly -- to the racial fears of white Philadelphians by portraying Street as an unrepentant radical. The fact is that Street was known in the 1970s as an effective community organizer, working with street-level activists in North Philadelphia for community empowerment during the hostile Frank Rizzo years. These credentials as a "black ex-radical," I submit, have helped to legitimize his fervent and often militant support for the actions of city and state police during this summer's protests. I find it difficult to imagine a bespectacled white suburbanite -- Republican mayoral candidate Sam Katz, let's say -- expressing such views without being compared to New York Mayor Rudolph Giuliani. Yet Street's complete turnaround is silently lauded; the public -- and perhaps Street himself -- believe that he has dissociated himself from his controversial past and remade himself into a defender of law and order. Consider the irony: Street used to organize and participate in protests. He had his run-ins with police. Today, he stands fully behind -- and denies -- police brutality and has used the recent protests to portray himself as a (black) politician who's not afraid to be tough on crime. Both before and after August 1, Street promised that those arrested would be prosecuted to the full extent of the law. Unfortunately, Philadelphia's mayor is not the only example of manipulation of racial fears by and among black Americans. Memos leaked from the D.C. and Philadelphia police departments revealed that African-American cops had been psychologically primed for demonstrations in their cities, told that they should be ready for a bunch of white kids who would taunt them with racial slurs. Why, in both cases, were black officers targeted? Perhaps Street's about-face does not evince anything deeper than the "maturity" of old age. After all, haven't countless other leftists forsaken their convictions upon taking power, from Vietnam protester Bill Clinton and ex-pothead Al Gore to the ex-pacifist European leaders who bombed Yugoslavia? Perhaps Street is simply guilty of hypocrisy. Recall that this defender of poor communities delivered the coup de grace to Chinatown this spring by championing the decision to put a new stadium next to the politically vulnerable neighborhood. Perhaps Street has forgotten what it's like to be an ordinary citizen. According to reports, when an aide was arrested for jaywalking at the convention in Los Angeles, an offended Street confronted the officer responsible, reminding him that he was the mayor of Philadelphia -- in other words, an important man -- whose aides were to be treated accordingly. It seems Street's experiences haven't prevented him from turning a blind eye to police excesses, whether against white protesters or poor African Americans. Taken in isolation, perhaps. But in the context of the rising tide of citizens committed to social change, John Street's vindictive and cowardly stance against the civil rights of political activists reveals that officials will use any means -- even reverse racism -- to keep down those who challenge their power.