What, at this point, is the rationale for having a “special counsel” investigate matters relating to Russian involvement in the 2016 election and matters stemming from the investigation of these matters? We don’t need a special counsel to investigate Russian interference in itself. The FBI and various congressional committees can handle that.

We don’t need a special counsel to investigate allegations of collusion by President Trump. After about a year of digging, no one has uncovered evidence of such collusion. Indeed, James Comey admitted that Trump wasn’t under investigation for collusion (or anything else).

We don’t need a special counsel to investigate people like Paul Manafort and Roger Stone. Comey said that President Trump was fine with letting the chips fall where they may as to these “satellite associates.”

Do we need a special counsel to investigate Michael Flynn? I don’t think so. Trump apparently said he hoped Comey would go easy on Flynn, but that ship has sailed. If Trump wants to intervene again on Flynn’s behalf, it will surely be at the pardon or commutation stage.

But let’s assume we need a special counsel to investigate Flynn. In that case, absent other potential crimes that require a special counsel, the scope of the special counsel’s investigation should be limited to what Flynn did.

What about obstruction of justice? In my view, allegations of this crime don’t warrant investigation by a special counsel (or anyone else). The allegations are founded on Comey’s testimony and his memos. But even if everything Comey says is true, it doesn’t state a case of obstruction.

Comey himself realized this. That’s why he didn’t report Trump, as would have been legally obligated to if he believed the president had obstructed justice.

But let’s assume we do need a special counsel to investigate “obstruction of justice.” Should Robert Mueller be the one doing the investigating?

The answer, it now seems to me, is: no. Why? Because he is a friend of James Comey, the key witness against Trump in any obstruction investigation.

If there is a case for obstruction, it begins (and probably ends) with Comey’s claims that (1) Trump demanded loyalty and (2) asked him to go easy on Flynn, coupled with (3) the firing of Comey. Trump disputes point (1), so it apparently will require an assessment of whom to believe — Comey or Trump.

Point (2) apparently will turn on assessment of Comey’s view that the president’s request was really a direction to go easy on Flynn. Was Comey reading Trump correctly or incorrectly? Did he really view Trump’s statement as direction at the time the two talked or is this an after-the-fact interpretation motivated, perhaps, by revenge?

Point (3) may require an assessment of the precise reason for Comey’s discharge — e.g., was it the director’s unwillingness to say Trump wasn’t being investigated; was it the director’s persistence in investigating Flynn; was it general dissatisfaction with the pace or course of the investigation? That assessment may be influenced by how one views Comey. A special counsel who likes Comey is likely to take a dim view of his firing and thus adopt the least charitable of Trump’s motive.

Because any “obstruction” investigation, and decision whether to prosecute, is so “Comey-centric,” it seems to me that the investigation, and decision whether to prosecute, shouldn’t be in hands of a friend of Comey. If such an investigation is to proceed, it should be headed by someone who has no personal relationship with either the president or Comey.

Keep in mind, too, that Comey and Mueller aren’t just friends. They are “comrades-in-arms.” They served together in the Bush Justice Department. During that time, they were partners in resisting the White House’s efforts to obtain reauthorization of the Bush administration’s warrantless surveillance program.

Comey and Mueller famously rushed to a hospital to prevent Attorney General Ashcroft from signing the reauthorization. And, as John reminded us here, when Comey tendered his resignation to President Bush as a protest to the way the White House was behaving on reauthorization, he leveraged it by saying Mueller was also going to resign.

In short, Comey and Mueller worked in tandem in the defining moment of Comey’s stint in the Bush Justice Department.

Also keep in mind how personal the dispute between President Trump and Mueller’s friend and former comrade has become. Among other things, the two have accused each other of being a liar.

For all of these reasons, I believe there is a serious question as to whether Mueller can be impartial in investigating and deciding whether to prosecute an obstruction of justice claim against Trump. The question is substantial enough that, now that it’s clear how central Comey’s role in such a claim is, Trump would be justified in firing Mueller.

This doesn’t mean it would be wise to fire him. The political blow back would be considerable, especially if Deputy Attorney General Rod Rosenstein felt compelled to resign. Then, we’d be in “Saturday Night Massacre” territory.

Firing Mueller might tilt the race for control of the House to the Democrats. Democrat control of the House would likely mean impeachment proceedings against the president (with the firing of Mueller as part of the pretext for impeachment). Although impeachment proceedings might hurt the Dems in 2020 — a much more significant election year than 2018 — a Democrat controlled House is not in Trump’s interest.

So prudence may militate strongly against firing Mueller. But how prudent is it for Trump to allow the fate of his presidency to rest in the hands of a friend and former comrade of Jim Comey?

UPDATE: I see that Byron York has written a piece called “Is Robert Mueller conflicted in Trump probe?” Byron interviewed five Washington lawyers Sunday — “lawyers in private practice, on Capitol Hill, in think tanks, some of them veterans of the Justice Department.” He reports that “the verdict came back mixed.”

In this post, I take no position on whether Mueller has a legal obligation to resign. That’s because I’m not an expert in legal ethics; nor did the research I performed yield a definitive answer.

My position is that, whether technically a conflict of interest that would require Mueller to withdraw or be removed, his friendship and association with Comey provides Trump with sufficient grounds to remove Mueller.