Robert S. Mueller III. (Charles Dharapak/Associated Press)

President Trump’s increasingly hostile rhetoric toward special counsel Robert S. Mueller III and his assault on the FBI (it’s in “tatters,” he falsely said) should raise concerns that he may contemplate firing Mueller. The Post reports: “Several law enforcement officials said they are concerned that the constant drumbeat of conservative criticism seems designed to erode Mueller’s credibility, making it more politically palatable to remove, restrict or simply ignore his recommendations as his investigation progresses.” By insinuating that the investigation will be wrapped up by the end of the year, Trump’s spin team seems to be preparing for the argument that the investigation has become a “fishing expedition.”

Senate Minority Leader Charles E. Schumer (D-N.Y.) warned Republicans on the Senate floor Thursday: “Spuriously attacking Robert Mueller, one of the most respected and trusted civil servants in our country, is the surest route to losing all of your credibility. I’d remind everyone on the right who are trying to muddy the waters on the Mueller investigation: Robert Mueller was a career prosecutor who’s served both Republican and Democratic administrations in the most trusted roles. … But this is bigger than one man, Mr. President. The attacks on special counsel Mueller and his investigation erode faith in the rule of law, that bedrock principle at the heart of our civic life.”

Republicans in Congress could and should dissuade Trump from taking this step. As Norman Eisen, Noah Bookbinder and Caroline Fredrickson point out in a new report for Citizens for Responsibility and Ethics in Washington (CREW):

Two bipartisan groups of senators have introduced legislation that would make it more difficult for President Trump to terminate Special Counsel Mueller. Senators Lindsey Graham, Cory Booker, Sheldon Whitehouse, and Richard Blumenthal’s Special Counsel Independence Protection Act would require the attorney general to file an action in the United States District Court for the District of Columbia to remove the special counsel. Senators Thom Tillis and Chris Coons’s Special Counsel Integrity Act would allow the special counsel to challenge his or her removal in court after the fact. In both cases, the termination would only be valid if the special counsel was removed for “misconduct, dereliction of duty, incapacity, conflict of interest, or other good cause, including violation of policies of the Department of Justice.” Passage of either bill would increase the obstacles to presidential interference with the Russia investigation.

Republicans could also state clearly now that they would simply rehire Mueller as counsel to one of the committees currently investigating the Russia scandal and potential obstruction of justice. Even more simply, Republicans could stand shoulder to shoulder with Democrats and inform the president that firing Mueller would set off impeachment proceedings. Indeed, if the president is going to impede again and again a legitimate investigation, then the only constitutional remedy is impeachment.

Since Trump’s lawyers range from incompetent to merely sloppy, CREW does them a favor by explaining that firing Mueller wouldn’t be so easy and would likely set off litigation without stopping the probe. To begin with, only the attorney general can fire Mueller, so Trump would have to order Attorney General Jeff Sessions to do so. If Sessions refused (which he might do, as he has already recused himself from matters involving the Russia probe), then it would fall to Deputy Attorney General Rod J. Rosenstein, and on down the line. This would be a rerun of the Saturday Night Massacre under President Richard Nixon and would set off a political firestorm. Here, when indictments and plea bargains have already been issued, such a move would widely be seen as an effort to stymie a productive law enforcement operation.

Moreover, Trump would need “cause” under the Justice Department regulations. (“The special counsel regulations specify that a special counsel may be removed ‘for misconduct, dereliction of duty, incapacity, conflict of interest, or for other good cause, including violation of Departmental policies’ and that the special counsel must be notified ‘in writing of the specific reason for his or her removal.'”)

As an alternative to firing him for cause, Trump’s lawyers might try repealing the regulation allowing for appointment of a special prosecutor. That has its own problems. (“First, based on his public statements and actions to date, it is likely that Attorney General Sessions would view himself as recused from any decision to repeal the regulations. Second, a repeal might be subject to procedural requirements imposed by the Administrative Procedure Act.”)

It’s not crystal clear that Mueller himself would have standing to sue in court (under a Fifth Amendment due process theory, in all likelihood) if fired for cause or in the event Trump short-circuited the special prosecutor regulation, but Mueller’s staff might. “Members of the special counsel’s staff may have third-party standing to bring an action for declaratory and/or injunctive relief on their own behalf and on behalf of the special counsel,” the CREW report posits. “Staff members could persuasively claim a close relation to the special counsel and a violation of their own rights stemming from a violation of Special Counsel Mueller’s rights—especially if a termination of the special counsel is accompanied by direct interference with the investigation. The principal challenge for such a suit would be demonstrating that the special counsel is unable to bring suit himself.”

Whether such suits would be effective is anyone’s guess, but the prospect of litigating the dismissal of the special counsel in federal court would very well set off a political firestorm not even Republicans would be able to resist.

Moreover, firing Mueller wouldn’t accomplish that much for Trump — other than ignite a move to impeach him. The authors of CREW’s report explain:

Based on the [Justice Department] regulations governing the appointment and conduct of the special counsel and (albeit limited) historical analogues, we believe that the Office and its staff would likely survive the firing of Special Counsel Mueller and that investigative materials created or collected in the course of the Office’s work would be preserved under the Federal Records Act. Moreover, actions taken (e.g., subpoenas issued) by a grand jury convened by Special Counsel Mueller would survive his termination, and records of such proceedings could be transmitted to any government personnel for the purpose of enforcing federal criminal law. . . .

A special prosecutor appointed to investigate misconduct involving the federal executive branch has been terminated only three times in U.S. history to date. In two of the three instances, the fired prosecutor’s investigations were simply picked up by a newly appointed prosecutor.

In sum, Trump would have significant legal and political barriers to firing Mueller, the most interesting of which could be a federal court judge finding the termination improper. Even if Mueller was fired, the investigation and its findings would live on. Nevertheless, Congress should be doing much more formally to rebuff Trump’s unsubstantiated accusations. On a bipartisan basis, lawmakers need to make clear that they will move swiftly if Trump tries to fire Mueller. Moreover, by moving ahead with one of the legislative vehicles to protect Mueller, lawmakers could head off a constitutional standoff.