We also asked an ACLU attorney, a private prisons expert, and the ex-commissioner of New York City's jails.

On the number of potential detainees

Hurwitz: “ICE wants to increase their capacity from about 41,000 people a day to 100,000—that’s pretty significant. To put it in comparison, BOP’s population today is about 155,000. And ICE doesn’t have 122 prisons like BOP has.”

Cho: “This is an extraordinary number of people. ICE is rounding up people through home raids, workplace raids, court check-ins, courthouse arrests, arrests near schools, places of worship. The other thing is that ICE is refusing to release people from detention who have traditionally been released, people who may be eligible for bond and parole, people who are very medically vulnerable, and even people who have won their cases.”

On where the money might end up

Hurwitz: “Remember, ICE doesn’t own prisons. So my guess is the immediate effort will be in contracting with private prison companies or states and localities that have capacity to hold these people.”