Two months into Donald Trump’s Presidency, John Kelly, then the Secretary of Homeland Security, publicly confirmed that his department was considering separating immigrant parents from their children at the border, as a way of discouraging families from crossing illegally. It was a radical idea, one that past Administrations had considered and then dismissed as too extreme and too complicated. After coming under intense criticism from the press, human-rights advocates, and members of Congress, Kelly backed off from it. But the idea persisted. A few months later, in August, 2017, a group of officials at the Department of Homeland Security gathered to brainstorm new ways to toughen immigration enforcement. Among those leading the discussion was an official named Gene Hamilton, a former aide to Jeff Sessions, the Attorney General, and a close ally of Stephen Miller, the President’s chief immigration adviser. “Hamilton told us that over the next few days we’d need to generate paperwork laying out everything we could do to deter immigrants from coming to the U.S. illegally,” a person who attended the meeting told me. Memos were drafted outlining a range of possible policies; one of them was separating parents from their kids at the border. “All the memos sucked,” the person said. “The outcome was predetermined. We didn’t have time to work out any of the policy differences. Some of the ideas didn’t make sense. Some were illegal, and some, like separating kids, were just immoral.” Many of the proposals, including the one involving family separation, “got bogged down in the clearance process, because of how difficult and controversial it was,” the person said. And yet every few months the idea would resurface in discussions. “It would rear its head again.”

Last summer, public defenders and immigration judges along the border began noticing an alarming pattern. Parents who had crossed into the U.S. with their children were arriving to detention facilities without them. The reason had to do with the Department of Justice, which was pushing U.S. Attorneys across the country to prosecute more border crossers for entering the U.S. illegally. In the past, many of these people, especially those with children, had been released pending the outcome of their civil immigration cases; now they were being arrested and held for extended periods by the D.H.S. The government was treating their children as though they’d come to the U.S. alone, as unaccompanied minors, and turning them over to the Office of Refugee Resettlement, a branch of the Department of Health and Human Services. There appeared to be no coördination between the different government agencies involved, so parents were losing contact with their own children. “They have no idea where their child is,” one assistant public defender, in Arizona, told the Houston Chronicle last fall. In one judicial order, a federal magistrate judge, in El Paso, Texas, asked the government, “What are the arresting agency’s procedures for providing information (e.g. location and well-being) regarding the unaccompanied minor children of undocumented alien defendants charged with a petty misdemeanor such as illegal entry . . . ?” Government lawyers didn’t seem to have an answer.

At first, the Trump Administration denied there was a formal family-separation policy in place. Then, as the evidence mounted, it claimed that it was only trying to protect immigrant kids from smugglers and imposters posing as their guardians. In February, the A.C.L.U. sued the government for separating a Congolese mother from her seven-year-old daughter, for more than three months, after they had arrived in San Diego seeking asylum. The mother was held in California, while her daughter was sent to Chicago. The D.H.S. claimed that it had doubts about whether the woman was truly the child’s mother, yet it waited four months to administer a DNA test. In April, the Times reported that more than seven hundred families had been separated since October, including more than a hundred children under the age of four. A government spokesperson responded, “D.H.S. must protect the best interests of minor children crossing our borders, and occasionally this results in separating children from an adult they are traveling with.”

Last month, the pretense fell away completely. On April 6th, Jeff Sessions and Kirstjen Nielsen, the head of Homeland Security, announced a zero-tolerance policy for immigrants at the border. Anyone who didn’t cross the U.S. border at an official port of entry would be criminally prosecuted, even if they were seeking asylum, and those travelling with their children would be separated from them. The policy was now official, and the Administration acknowledged its rationale: it was separating families to discourage others from travelling to the United States illegally. (A recent analysis, by Dara Lind at Vox, shows how the D.H.S.’s own data undermines the argument that this policy will act as a deterrent.) According to the D.H.S., six hundred and fifty-eight children were separated from their parents between May 6th and May 19th. Reports have surfaced of children, some as young as toddlers, being wrested from family members, and of parents being deported before they could locate their children, who remain stranded in the U.S. “Little kids are begging and screaming not to be taken from parents, and they’re being hauled off,” Lee Gelernt, a veteran attorney for the A.C.L.U., told the Washington Post. “It’s as bad as anything I’ve seen in twenty-five-plus years of doing this work.” Research has shown that removing a young child from her primary caregivers for even a short period can cause long-term psychological harm.

As my colleague Amy Davidson Sorkin has written, the message from senior Administration officials has been unapologetic. Sessions likened immigrants crossing the border with their own children to smugglers, warning them, “If you are smuggling a child, then we will prosecute you, and that child will be separated from you as required by law.” Nielsen, for her part, simply waved away questions about the policy’s impact on children. “What we’ll be doing is prosecuting parents who have broken the law, just as we do every day in the United States of America,” she said during a recent Senate hearing. “The child, under law, goes to H.H.S.”—the Department of Health and Human Services—“for care and custody.”

A Crisis at the Border More coverage of the Trump Administration’s immigration policy from The New Yorker.

Yet the network of child shelters overseen by H.H.S. is already operating at more than ninety-per-cent capacity. There’s been talk of sending children to military bases, where there’s more space. “In the immigration context, the government has never taken a stand against the protection of kids in this country,” Muzaffar Chishti, an immigration expert at the Migration Policy Institute, told me. “For the first time, it is now formally taking a position that explicitly goes against the best interests of kids.”

I asked the person who had attended the D.H.S. meeting with Gene Hamilton what had changed since last year, when the Administration was reluctant to publicly embrace the family-separation policy. The person pointed to the President. In the early days of Trump’s Presidency, migrants were anxious about how harsh his policies might prove to be. For a few months, illegal border crossings declined—a fact that Trump bragged about and took personal pride in. But by the end of the year the numbers had returned to levels roughly consistent with where they’d been just before he took office. Trump has complained that U.S. immigration laws are “pathetic” and riddled with “loopholes,” including, among other things, the “catch and release” of asylum seekers. He’s also held Nielsen personally responsible for the rise in migration from Central America. “What you’re seeing now is the President’s frustration with the fact that the numbers are back up,” the person told me. “The only tools the Administration has now, in the absence of legislation, is to make life miserable for people.”