Recently, two local civil-liberties groups exposed the extremes to which Boston police officers have gone to monitor gatherings, protests, and other lawful political activity in the city. The report by the state chapters of the ACLU and National Lawyers Guild painted an especially creepy portrait of the Boston Regional Intelligence Center, one of dozens of so-called fusion centers set up after 9/11 to coordinate local, state, and federal investigations.

Some of the past practices of the Police Department were clearly excessive; officers spied and wrote reports on acts of constitutionally protected speech, such as the run-up to a 2007 antiwar gathering at a Jamaica Plain church. Bostonians had many legitimate public safety concerns back then, and still do. But an appearance by the late social activist Howard Zinn wasn’t one of them.