When US Homeland Security secretary Kirstjen Nielsen pushed back on implementing a new, draconian White House directive on immigration, presidential aide Stephen Miller relied on a special trick to force her to relent, former agency officials told Quartz.

Miller would leak the latest numbers on apprehensions or asylum seekers at the border to reporters at the right-leaning Washington Examiner. The Washington Examiner would write a story, with an alarming headline about the growing number of people crossing into the US, sometimes criticizing Nielsen. Then Miller would print the story out, and get a paper copy to Trump.

Trump, ever sensitive to bad press, particularly from conservative outlets, would read the report, then pick up the phone and blast Nielsen, they said, and she’d capitulate on the issue at hand. White House and DHS spokespeople would not comment on the anecdote.

With Nielsen’s departure (April 7), Miller, a one-time aide to Jeff Sessions with close ties to the Center for Immigration Studies, an-anti immigrant group founded by a white supremacist, has emerged triumphant once again. Nielsen isn’t the only scalp Miller, 33, is going after—he is pushing a wholesale purge at the agency of over 200,000 employees that’s tasked with keeping US borders safe, detecting terrorism, monitoring transportation, and fighting cyber attacks, according to officials and other news reports.

Miller is agitating to remove Francis Cissna, a long-time DHS official who heads US Citizenship and Immigration, and he was also behind the push last week to bump nominee Ron Vitiello from the top job at Immigration and Customs Enforcement, former DHS officials tell Quartz. Randolph “Tex” Alles, the head of the Secret Service, another DHS agency, has just stepped down, and Homeland Security’s general counsel John Mitnick is expected to depart soon, at Miller’s urging, CNN reports.

An understaffed agency

The purge of top DHS officials is likely to leave the already understaffed agency reeling, and potentially unable to handle a natural or man-made disaster. If Cissna departs, the DHS will be without a permanent leader in most of its top jobs, including Secretary, deputy Secretary, head of FEMA, head of ICE, head of USCIS, Customs and Border Protection, and the Secret Service.

“It’s bad for morale, disruptive of departmental operations, and comes as the US is facing a variety of significant cyber and physical threats,” John D. Cohen, former DHS acting undersecretary for intelligence and analysis, told Quartz. The staffing decisions aren’t being made by “an individual who has an extensive understanding of the threats facing the country,” added the former counter-terrorism coordinator, they’re based “primarily on implementing a political agenda.”

“What’s to gain here?” said one former DHS official who worked with the Trump administration until very recently. “What’s plan B? Who do they have lined up to fill these jobs?”

Miller’s immigration overreach

“Without a doubt it is clear that [Miller] is in charge of immigration policy under the Trump administration,” said Philip Wolgin, the managing director of the immigration program at the Center for American Progress, a public policy research group. “From the beginning, when he was the architect of the Muslim ban, it is is amazing how singular a focus he has been on this.”

Miller has a “tremendous hold on this administration,” said Ur Jaddou, a former senior US immigration official and director of DHS Watch, a watchdog group. That’s thanks in part to the hard-line people he’s helped to install inside the administration, like Gene Hamilton, another former Sessions aide who worked on suspending protections for Dreamers, and Julie Kirchner, the former executive director of a fringe anti-immigrant group. Miller has a proven ability to destroy bipartisan efforts to get things done, Jaddou said, and “at every step of the way he just keeps doing it.”

In the early months of the Trump presidency, Miller rolled out immigration proposals that would ban non-English speakers and the poor, while declaring that the Statue of Liberty is not a symbol of welcome for refugees. In February of 2018 he torched a bipartisan Congressional deal that would have given Trump $25 billion to build a wall, in exchange for giving millions of “Dreamers” brought to the US as children a pathway to citizenship. In August of 2018, he proposed denying citizenship to anyone whose family had used US social services, including American citizen children. One White House aide’s tell-all book describes Miller as saying “I would be happy if not a single refugee foot ever again touched American soil.”

Before she was forced out of the agency in February of 2018, Elaine Duke, a long-time civil servant who briefly served as acting head of DHS, “would get in screaming matches with Miller in the White House,” over issues like how many refugees the agency would take, a former DHS official recalls. Duke would be yelling “That’s not who we are,” at Miller, the former official said, meaning his ideas were not in line with American values.

Even Trump immigration officials who support the president’s general policies on immigration, including limiting the number of people who can apply for asylum or who qualify for work visas, see Miller as a disruptive and dangerous presence. The most intractable problems that the US immigration system faces need to be fixed by Congress passing new laws, explained one ex-DHS immigration official who recently left the agency. But Miller’s hardline approach has made that more impossible, she said.