AT 7500 South Shore Drive, an apartment complex in Chicago, the front gate and door are wide open. Walk inside and you find an almost abandoned building. Though a few apartments have sturdy gates and double bolts, most lack doors and are closed by plywood. A few are open to the world. Inside one a bunch of balloons and a bouquet of roses suggest a recent celebration. A pushchair sits in one corner. A copy of the New Testament, in Spanish, lies on the floor. There is no sign of the occupants. Most likely they are in an immigration detention centre somewhere.