The federal government says it was arson. The protester charged with igniting a Molotov cocktail outside the District of Columbia police station during the recent race riots says it is protected First Amendment speech. Jarrett Jeremy Pace, on the night he set the fire, had said on Facebook he wanted to “burn a 12 station to the ground!” The number “12” is street slang for police. But now, Mr. Pace argues in federal district court he was speaking metaphorically, that he actually tossed the firebomb on the street near the Fourth District police station rather than at it, and that...