“It’s criminalizing mental illness,” the Cook County sheriff, Thomas Dart, told me as he showed me the jail, on a day when 60 percent of the jail’s intake reported that they had been diagnosed with mental illness. Dart says the system is abhorrent and senseless, as well as an astronomically expensive way to treat mental illness — but that he has no choice but to accept schizophrenic, bipolar, depressive and psychotic prisoners delivered by local police forces.