“More than 350,000 undocumented immigrants were detained between Oct. 1, 2015, and Sept. 30, 2016 — a number that could rise this year under President Trump’s immigration crackdown. As asylum seekers, visa violators and those charged with crimes wait for their cases to be heard in badly backlogged immigration courts, thousands are eligible for bail, just as they would be in criminal courts. Yet few can afford it.”