Attorney General Jeff Sessions went to the border in Arizona on Tuesday and declared it a hellscape, a “ground zero” of death and violence where Americans must “take our stand” against a tide of evil flooding up from Mexico. It was familiar Sessions-speak, about drug cartels and “transnational gangs” poisoning and raping and chopping off heads, things he said for years on the Senate floor as the gentleman from Alabama. But with a big difference: Now he controls the machinery of federal law enforcement, and his gonzo-apocalypto vision of immigration suddenly has force and weight behind it, from the officers...