The idea, out of the White House, was to arrest thousands of undocumented parents and children and deport them from the country in a swift and sudden campaign, meant as a show of force. According to exclusive reporting published by the Washington Post on Monday, a collection of Department of Homeland Security officials say that President Donald Trump and some of his closest advisers pushed for Immigration and Customs Enforcement to complete this sort of mass arrest campaign, but the plan was stymied when then-Secretary of Homeland Security Kirstjen Nielsen and then-acting ICE Director Ronald Vitiello challenged the idea in March. In early April, Trump ousted Nielsen, Vitiello, and a cadre of other high-ranking DHS officials.
According to the Post, Nielsen and Vitiello resisted the campaign mainly for "operational and logistical" reasons—not ethical ones. Those reasons likely have to do with ICE's funding constraints.
As I explained for Pacific Standard in February, each year, Congress funds ICE for a specific number of "detention beds"—in other words, Congress offers a funding limit for the number of people the agency can afford to detain. These "detention beds" are not literal mattresses (ICE essentially always has the physical space to detain more people), but rather a unit for quantifying funding. Congress will offer ICE a set amount of money to detain what's called its "Average Daily Population," and, right now, that means that ICE gets enough funding to maintain an ADP of 42,520 people.
But that's an average population—some days, ICE might be detaining more people, and some days it might be detaining fewer. But ICE will run out of funding if it maintains an ADP of more than 42,520 people for too long.
If ICE super-charged its arrest and detention program for a short time, as the White House proposed, that could have dried up all the funding the agency had to detain people through the rest of the year.
Overspending a budget has not stopped ICE before, however. In the past few years, ICE has overspent its detention budget so consistently and so significantly that even Republicans in Congress tried to rein in the agency.
From 2012 to 2017, ICE was funded for an ADP of 34,000. But at the end of 2016 and 2017, ICE announced that it had dramatically overspent its budget—it was detaining upwards of 50,000 people a day. In 2018, congressional Republicans raised the funding for an ADP of 40,520, the highest ever, but demanded that ICE keep to its budget and provide weekly reports to Congress on how the agency was "living within its means."
A mass arrest campaign over the course of a few weeks could put ICE so far in the red that the agency would not be able to divert enough funds from other areas in the DHS to pay for its detention later in the year.