Dist. Ct. did not err in granting defendants-police officer's motion for summary judgment in action alleging that defendants arrested on disorderly conduct charge plaintiffs-protesters on Chicago street in retaliation for asserting their First Amendment rights, and that plaintiffs were subjected to false arrest in violation of their 4th Amendment rights. Defendants were entitled to qualified immunity as to false arrest count where they had arguable probable cause to arrest both plaintiffs where: (1) one plaintiff was arrested after having previously been denied permit to conduct protest on site of arrest and had been arrested while attempting to organize impromptu protest rally that caused potential for disruption of pedestrian and vehicular traffic on Michigan Avenue; and (2) other plaintiff had failed to comply with police direction while attempting to cross police line that had been created to steer crowd to different part of City. Fact that portion of City ordinance that outlawed disorderly conduct had been subsequently found to be unconstitutional did not require different result. Also, both defendants were entitled to qualified immunity with respect to plaintiffs' First Amendment retaliation claim since law is unsettled as to whether existence of probable cause is complete bar to such claim.