As federal agents swarm American cities on the orders of President Donald Trump, it’s getting harder and harder to tell “law enforcement” from the criminals they claim to protect us from. In just the past two weeks, in Chicago alone, it’s all too easy to find accounts and videos of federal immigration authorities committing wanton violence rather than serving the public. On the city’s South Side, an apartment building was stormed in a late-night, military-style raid, with dozens of residents dragged indiscriminately from their beds and homes. Witnesses said they saw children separated from their parents and restrained by zip...