CNN  — 

President Donald Trump on Monday sought to downplay tension with Dr. Anthony Fauci after a White House official shared a statement that appeared to undermine the nation’s leading infectious disease expert.

“I have a very good relationship with Dr. Fauci, I’ve had for a long time,” Trump said at the White House during a roundtable event honoring police officers. “I find him to be a very nice person. I don’t always agree with him.”

A senior administration official also told CNN on Monday that recent frustration with Fauci does not stem from a lack of confidence in him. “It’s not a crisis in confidence or a warning shot,” the official said, adding it would be difficult to fire Fauci.

Under federal law, Trump doesn’t have the power to directly fire Fauci, a career civil servant, and remove him from government. And while Trump could try ordering his political appointees to dismiss the director of the National Institute of Allergy and Infectious Diseases, Fauci could appeal – a time-consuming process.

The President does, however, have the power to sideline Fauci, keeping him away from press briefings and media interviews – as has happened in recent weeks, though Fauci has proven adept at pushing his message through different channels.

CNN spoke with Max Stier, president and CEO of Partnership for Public Service, about the history of the federal government’s protections for civil servants and what might happen if Trump tried to go ahead with such a move. The conversation, conducted over the phone and lightly edited for flow, is below.

CNN: Tension between the President and Fauci has escalated in recent weeks and days. Could Trump fire Fauci and what would that look like?

MS: The President could not fire Fauci without cause. There are civil service protections for career federal employees that prevent them from being removed or demoted for political reasons.

CNN: When you say political reasons, what does that mean?

MS: I’ll give a tiny bit of history because it’s interesting and it goes back actually to 1881 when President James Garfield was assassinated by a would-be job seeker.

We had a spoils system that had dominated the government employment base and it didn’t work. You had people coming into positions of public import who were there not because of their capability but because of their political connections and in a remarkable turnaround, then-Vice President Chester Arthur, who was a product of that spoils system himself supported legislation – the Pendleton Civil Service Reform Act – that was a game-changer and professionalized the government employee base.

And it began a long process of making it more and more merit-based. And part of the outcome of that assassination then was a rule system that does not allow political leaders to remove or demote career civil servants without justification. And the justification has to be around poor performance, or failure to follow orders. And then there is a process that has to be followed even if there are allegations of performance or misconduct issues, and that process requires written notification and opportunity to respond.

So the President would not in this context be able to fire Dr. Fauci on the basis of not liking what Tony Fauci had to say.

CNN: So it sounds like there are quite a few protections that separate him from, say, a Trump Cabinet pick whom the President could fire via a Tweet.

MS: Exactly right. A Senate-confirmed political appointee serves at the pleasure of the President. So the President may fire really for any reason a senior political appointee.

CNN: If Trump did attempt to remove Fauci, could you walk through what that would look like? Would you have to go through Health and Human Services Secretary Alex Azar?

MS: The President of United States couldn’t directly fire a career civil servant. They would have to go to someone in their chain of command. And so in this instance you’d have HHS Secretary Alex Azar or the Director for the National Institutes of Health Francis Collins, who I might add is an extraordinary public servant himself. And Fauci was one of his mentors when he started.

So it’s worth noting that the NIH is not only an amazing science organization – best in class in the world – but it is almost entirely a career-led organization in government, and so therefore unusual in that respect. There’s next to no one who is a political appointee and when you have someone, it’s people like Francis Collins, who is a world-class scientist himself.

CNN: OK. And even if someone in the chain of command were willing to dismiss Fauci, there are channels for him to appeal it?

MS: That’s correct. So he would have to be given, first, notice of what the allegation was. It would have to be misconduct or failure to follow orders or whatever else it might be. Then you have an opportunity to respond. And if the decision was still made to fire him, he could go to the Merit Systems Protection Board and ultimately to a court to claim that he was fired in violation of the civil service rules.

Now, obviously we’re talking about firing him. It is clearly the case that the President, even if he can’t fire him for any reason, he can sideline him. He doesn’t have to listen to his advice, nor does he have to include him in the task force or otherwise allow him to be fundamentally in a deciding role. That is a choice the President or other senior political leaders could make.

CNN: It sounds like Fauci has recourse to a lengthy process if removing him is something the White House wanted to attempt. 

MS: It can be. And again, the individual – the employee – has to be willing to take on that process. 

But there are in place process protections to avoid instances in which employment becomes politicized. And again, it goes back to that root of a recognition that you want to have a merit based, um, civil service to make sure that Americans have the best decisions being made by their government. You want to have a professionalized and expert group of people in charge of issues of public import for just these kinds of circumstances we’re in today when we face incredible crises.

I think one useful reminder is that Anthony Fauci has been leading the infectious disease component of the NIH since 1984. And he’s been serving presidents for that entire time with expert advice.

And it is one of the ways in which our government is extraordinary. You don’t find Tony Faucis in very many places in this country or the world. He is considered a gem in the science circles that are now pretty central to our safety and security.

CNN: It’s striking the way Fauci’s reputation has become such an asset to him politically. There are real political consequences for Trump for sidelining Fauci given the trust the American people have placed in him. 

MS: It’s a really important point and also one we should be thoughtful about because there are many people who are equivalently capable in the federal government, but there are very few who have that trusted brand with the American public.

So the rules can provide a certain level of protection, but fundamentally the most important protection is the American public’s appreciation of the value of a merit based system. And if you lose that understanding and appreciation, then you can get leaders who can work  the system in ways that were not intended, or that can damage it severely.

CNN’s Jim Acosta contributed to this report.