It was mid-January and a partial government shutdown was stretching to record-breaking length . In the White House, officials were busy plotting ways to respond to House Speaker Nancy Pelosi, who had just issued a threat to shelve President Donald Trump's State of the Union address if agencies remained shuttered.

Mulvaney, the multi-titled aide and former congressman weeks into his post as acting chief of staff, offered colleagues a thought: because Trump was commander in chief, he could ground Pelosi's use of a military plane to visit troops in Afghanistan . Trump was thrilled with his new chief of staff's proposal, believing the idea to be brilliant. Watching a large blue bus idling at the Capitol as Democrats learned of the move, Trump happily believed he had gotten the best of Pelosi.

The glee didn't last. Pelosi's office later accused the White House of endangering lives by revealing her plans to travel to a war zone. Conceding to the speaker's prerogative, the President will not deliver his State of the Union speech on Tuesday, as originally planned and was invited Monday to do so the following week.

It was a small concession that came before a larger one: agreeing to open the government without securing any money for a border wall. For Mulvaney, it was a small and short-lived victory in what has been a singularly focused first month on the job.

With the shutdown ending without any money secured for a border wall, there are now questions of whether the month-long impasse was a waste of time. And Mulvaney -- a former three-term congressman who entered the job promising more political savvy than his predecessor -- is now under pressure to prove his management style will yield results.

Mulvaney's tenure as Trump's top aide has, until now, proceeded entirely during a partial government shutdown -- leaving the acting chief of staff both without a full staff and saddled with keeping track of which parts of the government were no longer functioning. Still running the Office of Management and Budget, Mulvaney was the official who technically had to shut down the government when funding lapsed in December.

Free coffee!

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As a welcome back gesture on Monday, Mulvaney invited staffers who had been furloughed for the past month for coffee in Navy Mess in the White House. For many it was the first time seeing the chief of staff in his new role.

Some inside the West Wing viewed the shutdown as advantageous for Mulvaney, who entered the job with a President solely focused on the border wall issue -- preferable, aides said, to other moments of Trump's presidency that have lacked focus or were easily derailed by his whims.

Over the course of the record-breaking standoff, Mulvaney often appeared on television to defend the President's position, including on Sunday. Trump has regarded his appearances as helpful and believes him to be an effective defender, according to a senior administration official. Mulvaney's TV appearances early in Trump's term were part of what brought him to the President's attention in the first place, the official said.

Mulvaney was not the President's top pick to replace John Kelly as chief of staff. But Nick Ayers, the vice president's top aide, refused to commit to a two-year timeline. And former New Jersey Gov. Chris Christie, who took a train to Washington in December for an interview with the President, had taken himself out of the running.

That left Mulvaney, Trump's budget director, who participated in several meetings on the looming government shutdown with the President toward the end of last year. The two had developed personal chemistry, and Mulvaney had pitched himself for the job six months earlier. Most White House staff figured he had been passed over, and Mulvaney himself had begun exploring other options, including becoming president of the University of South Carolina or replacing Wilbur Ross as Commerce secretary. Then, on a Friday afternoon in mid-December, he walked out of a meeting with Trump having accepted the top job -- at least for now.

Daily life

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Mulvaney holds senior staff meetings on Mondays and Thursdays at 9 a.m. and has been viewed positively by many in the building he now oversees. Two White House officials said there was a greater sense of unity among West Wing staff during the shutdown, fueled partly by a shared sense of purpose.

"People see Mulvaney as someone on their level -- more like a peer," one senior White House official said, contrasting that familiarity with Mulvaney's predecessor John Kelly, who aides inherently respected given his status as a retired Marine Corps general. Staffers rarely addressed Kelly by his first name, unlike Mulvaney.

In one of his first acts on the job, Mulvaney convened senior staffers at Camp David for an overnight retreat, a move well regarded among aides, some of whom have griped in the past about lack of communication and factionalism in the White House.

At the mountainside camp, aides played billiards and dined together in the rustic cabins. Some even brought their spouses. Instead of staying the night, Trump traveled up for several hours one day to spend time with the staff, praising them for their work and entertaining them with stories about how he came to own the palatial Mar-a-Lago club in Palm Beach.

He again harnessed the power of Camp David as the shutdown was ending -- on Friday, he brought Republican senators to the retreat to discuss their next steps.

Mulvaney has filled some senior roles in the West Wing with his own hires, many of whom came with him from the budget office and the Consumer Financial Protection Bureau, which he also ran. Most aides said they did not view this as unusual, but it has lent the West Wing a feeling of transition as Trump enters the second half of his first term.

In the past days, Mulvaney and other senior aides have tried to gauge which issues Trump wants to take up after the border fight is done, though he's offered little firm direction. With another deadline in three weeks, there is little doubt the border issue will continue to dominate.

And while Mulvaney retains the support of most staff, Trump has flashed his frustration at his habit of longwindedly delving into policy details -- something Trump similarly resented in other former aides, including national security adviser H.R. McMaster. During a meeting with lawmakers in the Situation Room this month, Trump abruptly cut Mulvaney off when he was discussing dollar figures for a potential deal.

"You're f***ing it all up, Mick," Trump snapped, leaving attendees feeling awkward, Axios first reported

Other White House officials have noted Mulvaney's tendency to get "long-winded" in meetings, which some predict may grate on the President.

"The President doesn't have patience for that," an official said. "Kelly is the opposite - a man of few words."

Mulvaney relished his time shuttling between the White House and Capitol Hill during the government shutdown. He had once been known in the Capitol halls as a sharp-elbowed conservative, but now he was leading negotiations for the White House alongside the vice president and Jared Kushner.

Seated on the opposite side of the negotiating table, Mulvaney often grapples with the rabble-rousing group he helped found during his six years as a congressman. The House Freedom Caucus frequently urges Trump to pick fights or back positions that the acting chief of staff may well have supported if he were still a tea party-aligned member, not trying to safeguard the interests of a Republican administration.

The contradiction between Rep. Mulvaney of South Carolina and Mulvaney the Trump administration official has drawn scrutiny since his earliest days as the budget director submitting requests for funding levels in excess of what he'd supported in the House.

More recently, Mulvaney reasoned that his previous view of a border wall as "simplistic" and "childish" had evolved after he learned more about illegal immigration.

"Things on the ground are different. And when the circumstances change, you change your opinion," Mulvaney said during a January 6 appearance on NBC's "Meet the Press."

Over the course of the shutdown, Mulvaney impressed some aides with his ability to provide the President with "an accurate picture of what to expect" from various courses of action, according to one person close to the White House. That was something his predecessor Kelly often relied on others to do.

Not managing Trump

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After Trump announced a proposed deal that would have traded wall funding for a temporary extension of some deportation protections, Mulvaney warned that some Democrats could try to filibuster the measure in the Senate. Kushner, on the other hand, insisted some Democrats would cross the aisle to support the proposal. Just one -- Sen. Joe Manchin of West Virginia -- ultimately backed the deal, which failed on the Senate floor.

Still, a senior White House official said Mulvaney is more deferential to Trump's whims than Kelly was, and holds his tongue on more issues than the President's son-in-law.

"Mick's not going to stand up to Trump as much and has not as Kelly would," the official said.

Kushner and Ivanka Trump made known in 2017 they would report up to Kelly when he was chief of staff, hoping to allow a more orderly system to take hold in the West Wing. This time around those assurances have fallen away, and there is little question the President's family members -- along with a constellation of Fox News hosts, conservative pundits, businessmen, golf buddies and others -- have regained full access to the President.

Mulvaney's position is "I'm not going to manage the President," one senior White House official said.

Some aides saw evidence of Mulvaney's penchant for allowing Trump to do as he pleases and speak with who he wants on his first full day on the job. On January 3, with the government shut down and many staffers on furlough, the President decided to appear in the White House Briefing Room for the first time, flanked by law enforcement officials who backed his demand to build a border wall.

Among them was Chris Crane, the outspoken president of the National Immigration and Customs Enforcement Council who harshly criticized the administration's choices to lead ICE. Kelly had long viewed Crane as a thorn in the administration's side, including during his tenure as Homeland Security secretary.

As chief of staff, Kelly nearly came to blows with Crane in the West Wing when Trump invited him for a meeting after seeing him appear on television.

"I can't believe you'd let some f***ing guy like this into the Oval Office," Kelly told Trump, according to Bob Woodward's book "Fear."

Mulvaney, however, has little interest in limiting the people who meet with the President or speak with him on the phone. In their conversations before being offered the job, Mulvaney told Trump he would not apply the same restrictions on Oval Office visitors or telephone calls that Kelly had, believing Trump operates better when he can do as he pleases.

He also discussed with Trump his view that the President's schedule be kept light, leaving time for the President to watch television and phone friends and outside advisers in the long stretches of "executive time" that form most of his mornings.

CORRECTION: This story has been updated to reflect that Nielsen did not attend Friday's retreat at Camp David with Mulvaney and GOP senators.