Deputy Attorney General Rod J. Rosenstein testifies before a Senate Appropriations subcommittee June, 13, 2017. (Bill O’Leary/The Washington Post)

White House press secretary Sarah Huckabee Sanders casually stated during the daily press briefing Tuesday that President Trump believes he has the authority to fire special counsel Robert S. Mueller III. That opinion isn’t shared by most legal experts, who argue, convincingly, that the only person who has such authority is Rod J. Rosenstein, the deputy attorney general who appointed him. Trump’s reportedly tried to pressure his White House counsel, Donald McGahn, to have Rosenstein ax Mueller, but McGahn pushed back. The New York Times reported Tuesday evening that Trump again called for action on Mueller in December but was dissuaded from doing so.

The question that naturally arises, then, is: Why not simply fire Rosenstein and replace him with someone who will fire Mueller? According to CNN, firing Rosenstein has been added to the list of remedies that Trump is considering in order to blind Mueller’s investigation.

It might also be the most damaging to Mueller’s efforts — even more than trying to fire Mueller himself.

Were Rosenstein fired, authority over Mueller’s investigation would kick down to solicitor general Noel Francisco until a permanent replacement was identified. Francisco would then be in the unenviable position of having to do his job while being buffeted by Trump’s angry outbursts.

Except that Trump might be able to quickly and easily get a more pliable person to fill Rosenstein’s shoes. A law passed in 1998 gives the president the authority to fill any vacant positions that require Senate confirmation with any other person working in the government who’s already been confirmed by the Senate. This is what Trump did with the Consumer Financial Protection Bureau: He used the Federal Vacancies Reform Act of 1998 to give control of the bureau to Mick Mulvaney — already confirmed as budget director — after its director resigned. So in theory Trump could fire Rosenstein and then quickly name, say, Environmental Protection Agency director Scott Pruitt as deputy attorney general.

There’s one caveat. It’s not entirely clear that Trump could use the Vacancies Act after having fired someone.

“The statute says that it applies when the current officeholder ‘dies, resigns or is otherwise unable to perform the functions and duties of the office,’” Paul Butler, professor of law at Georgetown University, told me in July. “That suggests that there might be a difference, and the Act might not apply if the person is fired.” Butler noted, however, that the debate over the law before its passage included consideration of this question — with some senators taking the position that vacancies from firings could be filled under its authority.

Let’s assume, then, that Trump fires Rosenstein — which, unlike Mueller, he has the authority to do. Let’s say further that Rosenstein is replaced with someone more than willing to provide the sort of political cover that Trump has long lamented he’s not getting from Attorney General Jeff Sessions. (Legal cover, mind you, that would be symptomatic of a deeply disconcerting abuse of power by the president.) How is this worse than just firing Mueller?

While Mueller’s mandate is obviously broad, there is a point of control over his actions within the Department of Justice. For most special counsels, that would be the attorney general. In this case, since Sessions recused himself, it’s Rosenstein — or whoever is in Rosenstein’s position. The law establishing the special counsel makes clear that Mueller has “the full power and independent authority” to perform his duties and that he can “determine whether and to what extent to inform or consult with the Attorney General” — in this case, the deputy attorney general — “or others within the Department about the conduct of his or her duties and responsibilities.”

That said, “the Attorney General may request that the Special Counsel provide an explanation for any investigative or prosecutorial step, and may after review conclude that the action is so inappropriate or unwarranted under established Departmental practices that it should not be pursued.” What’s more, Mueller can’t expand what he’s looking at significantly without getting sign-off from Rosenstein.

Louis Seidman, Carmack Waterhouse professor of constitutional law at Georgetown University, explained why this was important.

Trump moves someone in to replace Rosenstein, Seidman theorized when we spoke in February, “and that person would then say, ‘You can’t subpoena the president, and what’s more you can’t investigate his financial holdings.’”

Reached Tuesday evening, Seidman further suggested that Rosenstein’s replacement could reel in the authority that Mueller already had been granted. If Rosenstein said Mueller could dig into Trump’s real estate transactions, his replacement (say, Pruitt, for the sake of argument) probably could make those areas off limits. Pruitt could refuse to sign off on further prosecutions.

Or Rosenstein’s replacement could fire Mueller — although that would kick up much more of a firestorm. Firing Mueller wouldn’t by itself halt the process that’s already in motion, including the prosecution of Paul Manafort, for example, or the grand jury. But if Pruitt were not worried about the repercussions, Seidman said, he could unwind much of what’s already in motion.

“Depending on how aggressive this person wanted to be, they could dismiss the criminal cases, they could get rid of the grand jury,” he said. “In the end, if Trump is determined, the people he appoints could shut it down.”

“They can’t shut down a state investigation, and I think Eric Schneiderman” — New York’s attorney general — “would suddenly become a household name,” he continued. Shifting the investigations to the state level would have the additional downside for Trump of making it impossible for him to issue pardons.

It need not get that far for Trump to get what he wants, which is why replacing Rosenstein with someone who would handcuff Mueller (so to speak) might be the most effective way to stem the investigation. Less outcry, less heavy-handedness — and fewer indictments.

When we spoke in February, Seidman was blunt about the fallout if such a move were uncontested.

“We would wake up the next morning or a week later,” he said, “in a very different country than the country we live in now.”