When I turned on my phone after landing at O’Hare Airport on Wednesday, texts poured in from friends and colleagues warning that I was about to enter a region under siege. Many sent a video from that morning of immigration agents running into a day care facility in Chicago’s Roscoe Village neighborhood to pull out a teacher. It was the latest attack against the metropolis by President Trump’s deportation Leviathan, whose so-called Operation Midway Blitz this fall has made its earlier occupation of Los Angeles look like a play date. Armed agents have sauntered through downtown and manned a flotilla...