By Kaitlan Collins and Kevin Liptak, CNN

(CNN) -- A sense of uncertainty has engulfed the West Wing alongside a rash of recent staff departures, with many officials questioning who President Donald Trump will choose to fill key roles as his administration enters its second year.

Staffers have seen short-lists for vacancies and heard whispers of potential replacements for top jobs -- but they hear little from the capricious President himself about what he is looking for in his second string.

That's left outside advisers to ruminate and float their own choices -- often directly to Trump himself, either over the phone or during in-person conversations at the White House and his club in Florida. This has resulted in a clash between hard-right conservatives and more moderate voices, creating what staffers describe as a tribal-like atmosphere of division, friction and backbiting that mirrors the early days of the administration.

Economics

When Gary Cohn announced his resignation this week as director of the National Economic Council, a host of names appeared as potential replacements. The candidates' ideological range only underscored the competition to shape Trump's agenda.

Peter Navarro, once relegated to a minor role in the administration, has seen his stock rise as Trump moves forward with stiff new tariffs on steel and aluminum. The ascendance has led to speculation he may be tapped to replace Cohn, a prospect that sent jitters through the the council, which is staffed mostly by mainstream economists with experience in government.

Navarro said on Bloomberg television this week that he's not on a short-list to replace Cohn, but sources say he is privately angling for the role, though he's seen as a long shot.

"Giving Navarro the job would be the ultimate middle finger to the establishment and globalist power players who have run Washington for decades," a source familiar with the President's thinking told CNN. "I doubt Navarro gets the job. Trump understands the limits to Navarro's abilities, and (National Economic Council director) has a much broader portfolio than just trade. But there's a chance Trump won't be able to resist sticking it to them."

Questioned about concerns the President would stock his White House with vehement nationalists, White House press secretary Sarah Sanders insisted Trump would continuing relying on qualified aides.

"The President has got a number of very accomplished, smart, capable people around him. And he is going to continue to lean on a lot of those people," Sanders said. "But at the end of the day, the American people voted overwhelmingly for President Donald J. Trump. They voted for his policies, his agenda and for him to be the ultimate decision maker. And I think that everyone can rest assured in the American people's choice on that front, and that they've made the right one."

Others inside the White House are pressing to replace Cohn with someone in his mold: a mainstream economic thinker who can channel Republican economic concerns to the President. That might include Shahira Knight, who was instrumental during the tax reform battle but whom some consider unprepared for the top slot. A source familiar with the ongoing negotiations says she impressed Trump and chief of staff John Kelly by taking a leading role on tax reform. Though she is certainly Cohn's top pick to replace him, she does not have the business pedigree that Cohn did or the public profile the other contenders do.

The President values people who can make the rounds on cable television as Cohn did.

Trump himself suggested Thursday that he wouldn't place someone as head of his National Economic Council who is opposed to tariffs -- one of the principal reasons for Cohn's departure.

"I don't know if I could put him in that same position or not. He's not quite as strong on those tariffs as we want," Trump said.

That would rule out candidates like Larry Kudlow, the CNBC analyst who wrote an op-ed this week urging Trump to rethink his decision on tariffs.

Sanders said on Wednesday that Trump "has a number of people under consideration" to replace Cohn.

"He's going to take his time making that decision," Sanders said.

Communications

Throughout the Trump administration, the communications director position has been famously tough to fill. Jason Miller stepped down before the President was even inaugurated. Mike Dubke left after three months. An embattled Sean Spicer briefly held the title along with being press secretary. Anthony Scaramucci came and went in 10 days, with a profanity-laced tirade in between. Then Hope Hicks got the job because Kelly wanted to define her portfolio, though she was still seen as a surrogate Trump family member.

Now the position is open yet again, at a time when the communications team has been a source of frustration for many in the West Wing, including the chief of staff, with one official describing it as "the most derided and unprofessional" department in the White House.

Because she already has a role on the communications team, Mercedes Schlapp was initially seen as Hicks' natural successor. She has waged an internal public relations campaign for the position since Hicks announced her departure, at times meeting with her husband, Matt Schlapp, in her West Wing office and making the case for why she deserves the position to her colleagues.

However, staffers outside of the communications team have expressed frustration with Schlapp over the way she has handled her current portfolio, with some referring to it as "haphazard." To add to this, Schlapp does not have an intimate relationship with the President and the two disagree on immigration, a source familiar with their relationship tells CNN.

Others have floated the idea of Sanders taking on both roles, as Spicer did a year ago. There is internal speculation that Sanders will eventually want to transition to a more behind-the-scenes title.

National security

Meanwhile, a similar battle is playing out at the National Security Council, where H.R. McMaster's days as national security adviser appear numbered. Trump has clashed with him over a variety of issues, including Iran and Afghanistan. But the President is wary of pushing him to the exits without having a replacement lined up.

That's led to jockeying by sources inside and outside the White House to raise potential replacements that might get on Trump's radar.

Last week, those included Stephen Biegun, an auto executive who worked in the George W. Bush White House. People inside the White House knew little about Biegun when his name was raised as a potential hire last week. Kelly told associates he didn't know him.

Then eyebrows were raised after the President met with John Bolton, the hawkish Bush administration ambassador to the UN and current television commentator, in the Oval Office this week. Bolton has visited the West Wing frequently since Trump took office, and one source familiar said, "Trump has always wanted Bolton."

A White House official could not say if the President saw the meeting as a job interview.