One puzzle that deepens with Mike Schmidt’s New York Times story on “Trump’s Struggle to Keep [a] Grip on [the] Russia Investigation” is why Deputy Attorney General Rod Rosenstein has not recused himself from overseeing the Mueller investigation. On Lawfare’s special edition podcast Thursday, Susan Hennessey briefly raised the issue, but the puzzle is worth unpacking a bit more.

Recall that Rosenstein is the acting attorney general for this matter because Attorney General Jeff Sessions recused himself. As a result, Rosenstein appointed Mueller and, under the relevant order and incorporated regulations, supervises him.

Rosenstein was also centrally involved in James Comey’s firing. When President Donald Trump fired Comey, he relied on a letter from Attorney General Sessions recommending the termination, as well as an oddly written memorandum from Rosenstein, on which Sessions also relied, that was highly critical of Comey’s handling of the Hillary Clinton investigation. A few days later, however, Trump made clear that his reliance on Rosenstein’s letter was (contrary to what he wrote in his letter firing Comey) secondary at best. In an interview with Lester Holt, Trump said that “regardless of the recommendation” by Rosenstein, and apparently before it was written, he was going to fire Comey because of the Russia investigation. (The president’s words were: “in fact when I decided to just do it, I said to myself, I said you know, this Russia thing with Trump and Russia is a made-up story.”)

It later emerged that in May 2017, just before Trump fired Comey, Trump and an aide drafted an “angry, meandering” termination letter to Comey at the president’s golf club in Bedminster, N.J. The Bedminster letter was never sent. But in a meeting in the Oval Office soon after it was drafted, Rosenstein “was given a copy of the original letter and agreed to write a separate memo for Mr. Trump about why Mr. Comey should be fired,” according to the New York Times.

In short, before the Schmidt story, we knew that Rosenstein was intimately involved in the president’s decision to fire Comey. Rosenstein’s memo was used as a pretext to fire Comey; Rosenstein knew that the president wanted to fire Comey; and he read the Bedminster draft before he wrote his own memorandum.

In this light, it has been very puzzling for a while why Rosenstein does not have a conflict of interest in the Mueller investigation. The Washington Post reported unequivocally that Mueller’s investigation includes “whether President Trump attempted to obstruct justice,” including, as a central issue, in his firing of Comey. Rosenstein was in the middle of that firing. He possesses information about the president’s beliefs and motives in firing Comey, and quite possibly a personal interest in how those beliefs and motives are construed, since he appeared to many to have been used by the president (and was reportedly very angry about it). Rosenstein thus would very likely be a fact witness in any obstruction inquiry in connection with the Comey firing. It is hard to understand why he did not have a conflict of interest the moment Mueller’s investigation turned to obstruction in the firing of Comey.

Schmidt’s story Thursday added two details that make it even harder to see why Rosenstein does not have a conflict. First, Schmidt reports that, contrary to White House claims, Trump’s Bedminster letter mentioned the Russia investigation in its first sentence and described it as “fabricated and politically motivated.” Since Rosenstein saw that letter before he wrote his memorandum—and perhaps even discussed the contents with the president or attorney general prior to drafting his own second memo—he knew that the president had the Russia investigation on his mind in wanting to fire Comey. He wrote his memorandum about Comey in light of this knowledge.

Second, after reporting that Attorney General Sessions “wanted one negative article a day in the news media about Mr. Comey” and that a Sessions staffer approached a Hill staffer about whether he or she was in possession of any “derogatory information” about Comey, a claim denied by the attorney general’s spokesperson, Schmidt added:

Earlier that day, Rod J. Rosenstein, the deputy attorney general, had pulled one of Mr. McGahn’s deputies aside after a meeting at the Justice Department. Mr. Rosenstein told the aide that top White House and Justice Department lawyers needed to discuss Mr. Comey’s future. It is unclear whether this conversation was related to the effort to dig up dirt on Mr. Comey.

This suggests that Rosenstein had a more proactive role than has been previously believed in the firing of Comey. And it implies the possibility that he might have been involved in the effort to “dig up dirt” on Comey.

Rosenstein thus appears to be smack in the middle of Mueller’s ostensible obstruction investigation. Indeed, he appears to have contributed to the firing and provided a seemingly neutral basis for it, with the knowledge that the president was motivated at least in part by the Russia investigation. If the president abused his power in firing Comey due to the Russia investigation, Rosenstein appears to have knowingly contributed to it. I cannot fathom how, in this light, he remains the supervisor in charge of that investigation, since a reasonable person would question his impartiality in the matter.

One possibility is that Rosenstein has no conflict because Mueller is not actually investigating the president for obstruction. It has been widely reported for months in multiple reputable outlets that Mueller is conducting such an investigation. Schmidt’s story implies that he is and reports that Mueller has evidence in his possession that appears relevant only to an obstruction investigation.

However, Rosenstein’s order appointing Mueller was directed to “the Russian government's efforts to interfere in the 2016 presidential election,” not obstruction of justice. While the order contemplated that Mueller could go beyond the focus on Russian interference, there has been no official confirmation that Mueller is investigating obstruction by the president. Moreover, Rosenstein has expressly stated that “if anything that I did winds up being relevant to his investigation then, as Director Mueller and I discussed, if there's a need from me to recuse I will.” Since it is hard to see how Mueller could be pursuing an obstruction investigation related to the Comey firing in which Rosenstein is not “relevant,” Rosenstein’s non-recusal might, despite the many stories to the contrary, be evidence that Mueller is not in fact investigating whether Trump obstructed justice or otherwise violated the law in firing Comey. Marty Lederman made this very point last summer. He noted the many legal and political reasons why Mueller might not want to open an obstruction investigation and the lack of official confirmation of such an investigation. I agree and would add as another reason that such an investigation would entail the serious complication of Rosenstein’s recusal. And yet this analysis is hard to square with Mueller's apparent investigatory focus and evidence collection.

A second possibility is that Mueller is investigating obstruction by the president and that, with respect to that issue, Rosenstein has in fact recused himself but not publicly announced it. (One reason not to announce it might be that such an announcement would be official confirmation that Mueller is investigating obstruction by the president.) If so, then another Justice Department official, presumably Associate Attorney General Rachel Brand, would be supervising Mueller on the obstruction issue. I do not know if such a partial recusal is legally possible, since the appearance or reality of a conflict with respect to one element of the investigation might infect the appearance or reality of a conflict with respect to the entire investigation. Moreover, such a partial recusal, even if appropriate, would be politically controversial in the sense that many would make the “infection” charge to discredit the investigation. (It is also hard to see how news of the partial recusal would not have leaked.)

A third possibility is that Rosenstein is bending the rules a bit. With a president hostile to the investigation and the attorney general recused, Rosenstein (and Mueller) may feel that the situation is so fragile that everything possible must be done to avoid Rosenstein’s recusal, perhaps on the fear that a recusal would give the president ammunition to attack the entire investigation, or worse. If this is what is going on, then Rosenstein has surely obtained the appropriate authorizations from the appropriate Justice Department ethics unit. Such an authorization might satisfy any technical legal concern about a conflict of interest. But it would not satisfy the inevitable political concerns about such a conflict; indeed, it might fuel such attacks down the road in a way not helpful to the investigation.

Something here doesn’t make sense.