This is a tough question: What do police officers do when a group called Bible Believers, carrying a severed pig's head and yelling about a "pedophile prophet," are confronted at the Arab International Festival in Dearborn, Michigan, by Muslim children with rocks and bottles?
The "peaceful" proselytizers are kind of asking for it. But you don't want to crush their speech rights by giving in to the hecklers who are pelting them with rubble. Eventually, after things started to get out of hand, and the leader of the Bible Believers group was bleeding from a cut on his face, police stepped in and escorted the group out of the festival.
The original case split 2-1 in the Sixth Circuit, with the majority siding with the police officers and the dissent arguing that the cops didn't go far enough to protect speech rights. Now, the full Sixth Circuit will give the case the en banc treatment.