Some Greater Cincinnati residents are expected to take to the streets on June 14 to protest President Donald Trump, the latest in a series of anti-Trump demonstrations in the area over the past few months.

In a city notorious for unruly crowds at large sporting events, protesters were peaceful and law-abiding — as were the police.

Detectives don’t yet know why the alleged rifleman pulled out a weapon or ran from the peacekeepers, but they charged him with murder and accused him of creating the dangerous situation that led to A...