Jonathan Ernst / Reuters

Since November 2016, there’s been a running argument among those who are skeptical of Donald Trump but not implacably opposed to his presidency: Should they go into the system and try to restrain the president’s worst impulses, for the good of the nation? Or should they remain on the outside, and avoid the scarlet C of collaboration?

Secretary of Homeland Security Kirstjen Nielsen’s firing on Sunday should slam the door on that debate. Her tenure is the plainest example yet of the futility of trying to restrain Trump from inside—and the personal cost to those who try.

Over Nielsen’s 16 months in the job, the administration’s policy on the southern border has been a mess. The president has repeatedly threatened to close it, though at the moment he has backed down. He cut aid to countries in Central America’s Northern Triangle, which is only likely to increase immigration. There was a lengthy, pointless government shutdown over funding for a border wall. Border crossings, the metric the administration has chosen to emphasize as an indicator of an immigration crisis, are rising. Looming over all of this is the separation of thousands of families at the border last summer. And that list doesn’t even touch the chaos in other parts of DHS, such as FEMA, whose administrator resigned in February amid criticism of his spending and his handling of disasters.

Nielsen was not a Trump loyalist. She worked on homeland-security issues in the George W. Bush White House, which made her a good test for the restraint camp: She’s a professional bureaucrat and an expert in her field, rather than a Trumpist ideologue. Yet she leaves the administration inextricably associated with the most publicly reviled of the Trump administration’s many unpopular policies. Jeffrey Toobin summed up the damage to Nielsen on CNN: “[Trump] is the great reputation killer. Here is this woman who was a reasonably admired bureaucrat. For the rest of her life, people will look at her and think, Oh, that’s the woman who put children in cages.”

It’s remarkable how little Nielsen has to show for that. Trump’s border policies have been ineffective in stalling the flow of migrants to the border (though, as I have written, it’s not entirely clear that was their goal). Despite the policy of family separations, which the administration believed would deter asylum seekers, asylum claims soared in 2018, compared with 2017 (though there’s no telling how that number might have been different without the separations). Notwithstanding the pomp of Trump’s visit to Calexico, California, last week, no new sections of his beloved border wall have been built.

At times, Nielsen seemed resistant to the Trump agenda. In late 2018, Trump was reportedly close to firing her because of her reluctance to impose directives she believed were illegal. Nielsen quickly embarked on a campaign of tough talk that seemed to convince Trump she was a hard-liner, and he backed down. The problem was that to prove her loyalty, she had to hug Trump harder, thus further reducing any ability she had to restrain him.

The argument for the inside strategy was that, eventually, Trump would come to understand his job better. In the case of immigration, that didn’t mean trying to convince him out of his hard-line approach—Nielsen seems to have largely shared the president’s view that a drastic and quick reduction in illegal immigration and asylum seekers was necessary and possible—but to steer him away from the pointless and/or illegal tactics he favored and toward more effective ones that could achieve the same goals.

But Trump seems to have learned little over the past two years. He continues to prattle on about the wall. During his Calexico visit, his comments suggested he incorrectly believes that the Flores settlement, the 1997 legal agreement that limits the detainment of children, is named for a judge. According to NBC News and CNN, Trump has recently been pushing for DHS to reinstitute family separations, even though courts have repeatedly ruled they are illegal, and even though he claimed, when he halted the practice in June 2018, that “I didn’t like the sight or the feeling of families being separated.”

Nielsen apparently had a breaking point. According to multiple outlets, Nielsen went to the White House on Sunday for a meeting with Trump, prepared to resign but not set on it. One bone of contention was asylum, with the president pressuring Nielsen to block migrants from seeking the protection, which is clearly against the law. She had previously been willing to make the tortured argument that the border separations were not only legal but also required by law—though federal courts later rejected that reasoning—but the asylum issue was apparently too great a stretch.

Nielsen’s apparent pang of conscience was too late. Rather than allowing her to resign or make her case, Trump tersely announced, via tweet, “Secretary of Homeland Security Kirstjen Nielsen will be leaving her position, and I would like to thank her for her service.” He said that Kevin McAleenan, currently the commissioner of Customs and Border Protection, will serve as acting secretary.

Nielsen follows other administration officials who’ve left with their reputation besmirched. She became DHS secretary after her mentor, John Kelly, left the same post to became White House chief of staff, another thankless job that destroyed a reputation. Former Secretary of State Rex Tillerson was fired for trying to block Trump’s most self-destructive foreign-policy ideas. So was former Defense Secretary James Mattis, though he escaped with his reputation largely intact. Former Attorney General Jeff Sessions was a Trump loyalist, but was still unceremoniously tossed after nearly two years of browbeating. Former Press Secretary Sean Spicer, finding the usual opportunities to ex-spinmeisters foreclosed, ended up a special correspondent on Extra.

Trump will likely name a new secretary sooner or later. Nielsen’s experience should end any expectation that that person will be able, or will even try, to restrain the president’s approach to the department. The new secretary will enter the job with a clear picture of what his or her relationship with the president is—and what the likely effect on his or her own good name will be.

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