Trump in the Oval Office
© Getty ImagesPresident Donald Trump makes a call in the Oval Office on Jan. 28 alongside, from left, Chief of Staff Reince Priebus, Vice President Mike Pence, chief strategist Steve Bannon, press secretary Sean Spicer and then-national security adviser Michael Flynn.
When Omarosa Manigault, the former "Celebrity Apprentice" antihero-turned-White House adviser, needs to talk to President Donald Trump, she simply strolls into the Oval Office.

As assistant to the President and director of communications for the office of public liaison, Manigault enjoys what Trump aides refer to as walk-in privileges — meaning she doesn't need an appointment or permission to pop her head in and consult with the leader of the free world.

Her level of easy access marks a break from the previous administration, where President Barack Obama and his gatekeeper chiefs of staff kept at bay the number of aides, even senior officials, who simply walked in without an appointment. In contrast, Trump may have set up the most accessible Oval Office in modern history.

Along with Manigault, White House officials say, the list of aides with walk-in privileges includes chief strategist Steve Bannon, senior policy adviser Stephen Miller, chief of staff Reince Priebus, son-in-law and adviser Jared Kushner, and counselor Kellyanne Conway.

White House Counsel Don McGahn has walk-in rights, as does senior communications aide Hope Hicks, and Keith Schiller, Trump's longtime private security aide who followed him to the White House. Trump's new national security adviser, Gen. H.R. McMaster, is also expected to be added to the informal list, according to a White House official.

Press secretary Sean Spicer, often accompanied by Priebus, is another regular visitor to the Oval Office, as is chief economic adviser Gary Cohn and deputy chief of staff for operations Joe Hagin, according to a White House aide.

Even lower-level White House staff who don't visit the president's office regularly said they can get permission to go in from his assistant in circumstances when they need it. As one White House staffer put it, "I've never been told no."

There's no formal list of who is allowed in—or who is to be kept out. But many of the aides with free access frequently talk about it as a way of signaling influence with their boss.

A White House official declined to comment on the record but said: "The president likes to be accessible, including with his staff, and will continue that." Trump, famously, has said his team has no formal chain of command. But his loose approach means no single person in the White House controls the flow of information into the Oval Office.

Republican operatives outside the administration said they worry that may hamper a president known for his short attention span and instinctive decision-making.

"I believe in a strong chief of staff model, and I believe in it in a way that is beyond policy—just to serve the president and make sure only issues that should get to him get to him," said a former Bush administration official.

But this is how Trump, 70, has always worked. At his office in Trump Tower, former staffers said, it was rare the boss would not welcome an aide into his 26th-floor office. Trump wrote about his open-door policy in "The Art of the Deal" — on the first page. "Most people are surprised by the way I work," he wrote. "I play it very loose... I try not to schedule too many meetings. I leave my door open... I prefer to come to work each day and just see what develops."

Oval Office walk-in privileges have become part of the pop culture's understanding of life in the White House. In the final episode of "The West Wing," the president's assistant tells her successor that her first order of business is deciding who gets access. In the fictional Bartlet administration, walk-in privileges are awarded only to the First Lady and the chief of staff. In Trump's White House, the point is moot as the First Lady, still residing in New York City, has only been back to the White House once since Inauguration Day.

But the fabled term "walk-in privileges," has meant different things in different administrations. Obama favored a chief of staff who served as an iron gate. Advisers who needed time with him were stacked together in what his last chief of staff, Denis McDonough, referred to as "tiered wrap sessions" at the end of the day, with pre-scheduled time slots for groups of aides or individuals, according to former communications director Jen Psaki.

Senior advisers like Psaki, political director David Simas, senior adviser David Plouffe, press secretary Josh Earnest, and national security adviser Susan Rice could always get on the president's schedule via his assistant if they needed his time.

"It doesn't mean literally walking into the Oval," explained Psaki. "It means you're asking to see the president's assistant. It's still significant to be somebody the assistant would say, 'Sure, let me see what's possible on his schedule.' For no president, does complete and utter chaos, where people are streaming in and out, work."

In Obama's White House, the pecking order was determined not by who entered the Oval Office, but which aides Obama would seek out himself, in their offices, former aides said.

President George W. Bush had a small handful of trusted aides whom he wanted to have unfettered access to him — typically in the mornings— but asked that they debrief his chief of staff on their conversations with him.

"In the early mornings, he didn't have meetings scheduled and I would stop in," recalled Karen Hughes, who served as a counselor to the president. "But I would also stop by as events took place throughout the day, when I felt I needed to talk with him or let him know something."

Conway, who often brings up her walk-in privileges on television and in interviews, said that she tries not to overdo it. "I try to bundle my items as one and present them all together," Conway said in an interview. "If he is running behind on schedule, I triage and talk later or table it for later. Time is his most precious resource. Respecting it means helping to reserve it by triaging and sensing and conferring with people like Reince and schedulers. Privileges should be seen as exactly that."

Outside observers note that a system that worked for Trump at his real estate organization may be irrelevant in the unique work setting of the Oval Office.

"Walk-in privileges, for a president or a top CEO, should be for deeply trusted advisers whose presence in the room only adds to and improves the decision-making capabilities of the group writ large," said Juleanna Glover, a political strategist who served as press secretary to Vice President Dick Cheney.

Yet Trump's system reinforces competition among aides for the boss's favor — something that hasn't changed since his "Celebrity Apprentice" days.

On one episode, Manigault demonstrated a clear understanding of how to manage it. "Nobody likes you but me, Omarosa, so maybe they're not going to like you," Trump told her when she volunteered to be the leader of a women's team.

"Hey, that's all that counts, is that you like me," Manigault replied. Her appeal to Trump's vanity worked. "That is all that counts, actually," he replied. "In this game, that's all that counts."