And she controls time with Kelly the same way Kelly is seeking to control time with President Donald Trump — staffers who linger too long in the chief of staff’s office are interrupted and hurried along.

“Gatekeepers are generally not beloved,” said Jonathan Hoffman, assistant secretary of public affairs at DHS, who was hired by Nielsen. “But that’s why it’s an important job.”

Many of Trump’s top aides said they have been eager to fall in line with Kelly’s new, more disciplined structure, and still express great admiration for the general, who replaced former chief of staff Reince Priebus in late July. But they said they have been disappointed by an “us v. them” attitude from his deputy, and a sense that she has been brought in to “clean up all the messes.” And while Kelly has managed to control the information flow to the Oval Office and won the confidence of the president, the growing frustration shows that work still needs to be done to put together a happy, supportive team.

So far, Nielsen has been overseeing who is supposed to attend what meetings, ensuring the right agencies and departments are looped in, and reviewing how different offices are structured.

It’s a job that by nature breeds enemies, not allies. But Nielsen has been greeted by an especially vociferous backlash from a group of people who say they are not simply bridling at a new structure. Some Trump loyalists even refer to Nielsen behind her back as “Nurse Ratched,” a reference to the malevolent head nurse in “One Flew Over the Cuckoo’s Nest,” who coldly presides over a mental hospital.

Others compare the walls she has tried to erect around Kelly to the dynamic between Secretary of State Rex Tillerson and his top gatekeeper at the State Department, Margaret Peterlin, who controls all access to the secretary.

“At Homeland, she actively ensured that no Trump supporters were appointed or hired,” said political operative Roger Stone, one of Trump’s earliest advisers. “Like [national security adviser H.R.] McMaster and Kelly, she is a neocon who likely did not vote for Donald Trump and certainly does not support his non-interventionist worldview. If the president fails, it will be because of appointments like this.”

But it’s not only the hard-right Trump advisers who are frustrated. Senior administration officials who described themselves as cheering for the Kelly regime to succeed have been disappointed by what they see as a lack of communication with other senior aides, and a lack of respect for staffers who predated her.

Nielsen’s defenders chalked up the criticism to a discomfort with change, and said they expect it to pass. “Kirstjen is a great addition to the White House and has been helpful in bringing fresh perspective and new structure to the team,” said press secretary Sarah Huckabee Sanders.

Nielsen’s first impression in the West Wing stands in contrast to how she was viewed in her old life, as a trusted national security and cyber expert. An alum of the George W. Bush administration, where she served on the White House Homeland Security Council, Nielsen in recent years has advised government officials abroad and at home, as well as private sector CEOs, on infrastructure protection, including cyber security.

“I don’t think she’s a political person by nature,” said Frank Cilluffo, director of the Center for Cyber & Homeland Security at George Washington University, where Nielsen served until recently as a senior fellow. “She’s very competent and thoughtful. I’m not sure what the right training grounds are for anyone in these sorts of jobs, but she’s solid. She’s a wonk at heart, and she’s there to serve.”

Many of Nielsen’s former colleagues describe her as one of the hardest-working people they ever met. That was part of what impressed Kelly about her during the transition, when Nielsen volunteered to help oversee the confirmation process for Kelly, the incoming secretary of homeland security. The back-to-back late nights caught up with her and she fell ill, coughing so hard that she cracked a rib.

Instead of taking time off, however, Nielsen showed up to work with a bandage wrapped around her torso, to control the acute pain in her rib cage. “She got patched up and kept going,” recalled Thad Bingel, a DHS veteran who volunteered alongside Nielsen on the Trump transition team. “If you’re a guy who came up through the Marine Corps, like Kelly, you’re impressed with that.”

The painful rib incident, colleagues said, was part of why Kelly put his faith in the hard-working “sherpa” behind his smooth confirmation process — plus the fact she got results. Kelly, alongside retired Gen. James Mattis, were the only two Cabinet secretaries sworn in on Inauguration Day.

But while she has the backing of Kelly, so far she has established no personal relationship with the president — an oversight that longtime Trump world advisers describe as a major misunderstanding of how the structure around him functions, where all power ultimately emanates from him.

White House counselor Kellyanne Conway, a veteran of Trump world, said she disagreed with that categorization of the new enforcer’s enforcer. “She’s hardly parachuted into the White House uninitiated,” Conway said. “She’s been the chief’s chief at DHS for the first six months of this administration, when many of the major issues, like the travel ban, wall construction, ICE, FEMA and DACA, were running through that Cabinet department.”

She added that Nielsen “neither expected nor sought her new position, but not unlike her immediate boss, Kelly, she is motivated by duty, honor and country.”

Indeed, much of the early criticism directed at Nielsen is inherent in the difficult position she has been thrust into. A White House chief of staff functions essentially as a principal, making his deputy a de facto chief, a proxy in meetings, his eyes and ears on the ground.

“It’s true that it’s easier to train your ire on her than on a four-star general,” one White House official said. “Her boss is often with our boss. She’s left managing the store, she’s left telling people ‘no.’”

Some Trump veterans compared the dynamic to the one that ultimately drove Katie Walsh, Priebus’ deputy who colleagues described as “affably no-nonsense,” out of the White House after 60 days on the job. The difference is that Kelly has empowered Nielsen, where Priebus would often undercut Walsh, in an attempt to hold on to his own job — an ultimately doomed effort.

For now, it’s not only staffers who are pushing back against the tone and tenor of the new regime. Despite the new controls on his time and schedule, Trump has still spoken to his old advisers, like Priebus and Bannon. Longtime friends can still connect with him through the White House switchboard. The president even phoned his former aide Sebastian Gorka after his departure, according to someone familiar with the exchange, to express his thanks and hope for his support from the outside.

But people close to the administration said Trump is eager to make the new situation work and knows that change is necessary, even if it’s not the free-flowing, open-door structure he transplanted from Trump Tower to the Oval Office. Trump has great faith in Kelly, aides said, who has great faith in his team. Plus, the president “is aware of public perception,” one ally said. “And that perception is that if he fires them, something is wrong with him, not them.”