Forget Jacob Marley. This holiday season the Chicago Police Department is entertaining its own ghost from the past.

The department's notorious Subversive Activities Unit (commonly known as the Red Squad) was a Richard J. Daley-era corps that kept dossiers on more than 250,000 private individuals and lawful organizations in systematic violation of the First Amendment. The Red Squad was killed by a court-ordered "consent decree" in 1981, but two closely related cases are testing just how deeply it was buried.

In March 1997, the city petitioned the District Court to relax the decree, which

Chicago police blanketed the city during the 1996 Democratic Convention. STEVE ANDERSON

proscribes law enforcement from gathering intelligence on or disrupting any First Amendment activities unrelated to a criminal investigation. The thrust of the suit, rejected in September 1999 and currently on appeal, is that the police department has cleaned up its act: "There is no likelihood," reads the petition, "of the City's returning to the activities that prompted" the decree.

Not so, says a coalition of activist groups who have taken the city to court, charging "political spying and disruption" by Chicago police during the 1996 Democratic National Convention. Officers allegedly stormed the Active Resistance Counterconvention, after extensive surveillance of its organizers; pepper-sprayed the participants and destroyed personal property; and subjected several in attendance to lengthy interrogations. Besides suing for damages, the plaintiffs have asked the court to order more rigorous enforcement of the consent decree--just the opposite of what the city's petition requests.