We need a Robert Mueller resignation or a second special counsel The only way to avoid a tainted investigation or a political explosion is another counsel to investigate possible obstruction of justice.

Glenn Harlan Reynolds | Opinion columnist

Show Caption Hide Caption Ted Lieu: Impeachment process will start if Trump fires investigators Representative Ted Lieu of California said he believes Congress will start the impeachment process if President Donald Trump fires special counsel Robert Mueller and Deputy Attorney General Rod Rosenstein.

Special Counsel Robert Mueller has a problem: He has a disqualifying conflict of interest regarding a large part of his work. It involves a choice between investigating or relying on former FBI director James Comey, a longtime close friend of Mueller’s.

Ideally, he’ll recognize that and resign. But if he doesn’t resign, Attorney General Jeff Sessions should appoint another special counsel to take over the obstruction-of-justice part of the investigation, where Mueller is disqualified.

At present, there are two investigations: One into whether the Trump campaign colluded with the Russians (a claim that even Democrat Chris Matthews admitted fell apart after Comey’s recent testimony) and an investigation into whether, while being investigated for this claimed collusion, President Trump or someone else obstructed justice. That investigation is closely tied to Comey, and so is Mueller.

As Bill Otis wrote in these pages last week, Mueller is too close to Comey to be impartial, and that violates Justice Department conflict of interest rules. As Otis noted, “Comey and Mueller have been friends for nearly 15 years. They were partners in the episode that defined Comey's professional persona more than any other in his public service. It would be surprising if it had not also forged a permanent bond with Mueller ... Comey now finds himself at the center of the Russian investigation over which Mueller presides. Questions swirl around Comey — about whether the president wanted/hinted/hoped/asked/directed/or something else the investigation of former national security adviser Michael Flynn to be stopped/abandoned/slowed/soft-peddled/something else. This is probably the central element of the obstruction of justice case that Trump's opponents would like to see made against him. Questions also swirl about Comey's notes about this conversation and why he gave them to a private individual ( professor Dan Richman of Columbia Law) to convey to journalists. Additional questions have arisen about whether this curious and seemingly devious means of putting the contents of the notes in the public domain (leaking, in other words) was designed specifically to bring about the appointment of a special counsel outside the president's direct reach — and, indeed, whether Comey wanted, expected or intended his friend Mueller to get the job.”

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And as Otis notes, the Justice Department’s rules forbid a person from participating in an investigation if doing so "may result in a personal ... conflict of interest, or the appearance thereof." Mueller clearly has one here.

And yet, despite a clear requirement that Mueller be “disqualified” from this investigation, his dismissal by either Trump or Sessions on the heels of the president’s firing of Comey would create a political firestorm that the president — even if entirely innocent of any wrongdoing whatsoever—might be unable to survive.

And Mueller can’t fix things by simply recusing himself from the “obstruction” investigation, while delegating it to a subordinate. Perhaps unwisely, he has chosen lawyers who records show have contributed substantially to Democratic campaigns. Indeed, two have given the maximum $2,700 donation to Hillary Clinton last year, while another worked for the Clinton Foundation. No one could accept them as impartial towards the man who defeated her.

So if he cares about the rules, Mueller needs to resign. But if he doesn’t, there is another way — and it may be the only way — to avoid either a tainted investigation or a political explosion.

Sessions can and should appoint a second special counsel lacking Mueller’s close relationship to any person “substantially involved in the conduct that is the subject of the investigation” of the “obstruction” issue, leaving the original investigation of “collusion” in the hands of Mueller.

Because the facts surrounding the “collaboration” and “obstruction” investigations involve entirely different time frames, the investigations can be severed. Sessions recused himself from the “collaboration” issue because he was involved in the campaign being investigated. This rationale does not apply to the events that occurred months later, well after the inauguration. Therefore, he, rather than Deputy Attorney General Rod Rosenstein (who appointed Mueller), should select the special counsel.

And there’s much more to this choice than just the Justice Department's ethics rules. We have a deeply divided nation, and Trump’s supporters already see this investigation as a witch hunt, an attempt at a lawyer’s coup by the “Deep State” that has always opposed Trump’s presidency. An outcome that looks rigged could produce an even bigger explosion than Trump might produce by firing Mueller.

If Trump is cleared by a new special counsel, the country will be spared a great political trauma. Should the investigation go the other way, however, only a new special counsel — preferably one from outside the Beltway — can hope to placate the millions of Americans who cast their votes for Donald Trump.

Will Mueller step down, or will Sessions appoint another counsel? What happens next will tell us a lot about both men.

Glenn Harlan Reynolds , a University of Tennessee law professor and the author of The New School: How the Information Age Will Save American Education from Itself, is a member of USA TODAY's Board of Contributors. Follow him on Twitter: @Instapundit

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