03/22/2011 09:44 am ET Updated May 25, 2011

On Iraq War Anniversary, Judges Allow Suit By Protesters Against City Of Chicago To Go Forward

Just days before the eighth anniversary of the United States' invasion of Iraq, a panel of appellate court judges ruled that a group of protesters from the war's earliest days can sue the city of Chicago for mass arrests during that unrest.

Judge Richard Posner penned the decision, overturning a lower court ruling to throw out the class-action suit by the over 900 people who were arrested on March 20, 2003 protesting the beginning of the war. The ruling in favor of the city "was erroneous and must therefore be reversed," Posner wrote.

Eight years ago, protesters gathered for a spontaneous rally downtown as soon as the invasion began. City ordinance requires that even for impromptu gatherings, a permit be sought two days in advance, but as the decision reads, police often informally waive this requirement to allow protests that gather at a moment's notice.

The protesters marched up Lake Shore Drive, and headed west on Oak Street. But police, wary that they might access Michigan Avenue and disrupt traffic on that major artery, allegedly cut the protesters off and diverted them back toward Federal Plaza where the protest began.

A group of protesters, numbering roughly 1,000, headed west on Chicago Avenue to return to the Plaza. But police allegedly trapped this group of protesters, and began rounding them up for arrest. WBEZ reports that roughly 900 people were arrested and held for some 36 hours; many of them were charged with disorderly conduct, but ultimately charges against all of them were dropped.

In his decision, Judge Posner largely faults the city's laws. "The underlying problem is the basic idiocy of a permit system that does not allow a permit for a march to be granted if the date of the march can't be fixed in advance, but does allow the police to waive the permit requirement just by not prohibiting the demonstration," he wrote. But he also argued that the police were not without culpability: "The indifference of the superintendent and his subordinates to the danger to public safety and convenience of a mass antiwar demonstration cannot be attributed to the ordinance, defective as it undoubtedly is."

A crowd gathered downtown over the weekend, in part to celebrate the ruling, and in part to mark the eighth anniversary of the war's beginning. ABC-7 reports that over 1,500 people and 70 organizations rallied on Saturday to speak out against the war. No arrests were reported.

Note: The original headline for this story said "On Iraq War Anniversary, Judge Allows Suit By Rioters Against City Of Chicago To Go Forward." There were no "rioters" mentioned in the piece, and the headline has been changed to reflect that. We regret the error.