Devin Nunes announced that he was asking other members of the House Permanent Select Committee on Intelligence to "temporarily take charge" of the committee's investigation into Russia's attempts to influence the 2016 presidential election. Nunes said that he was doing this because "leftwing activist groups" had filed complaints about him with the Office of Congressional Ethics (which charges, he insisted, were "entirely false"). Nunes doesn't say which groups he means or what the charges were, but a statement issued by the chair and ranking member of the House Committee on Ethics says it's about whether Nunes made "unauthorized disclosures of classified information”—though again, the committee's statement doesn't say what disclosures they mean or who (if anyone) made the complaints. But it’s a fair bet that this is related to Nunes’ bizarre public disclosures of information gained from FISA warrants.
The first important question is what Nunes means, exactly, by asking other people to "temporarily take charge." Does he mean he's recusing himself from further work on the investigation, as was reported (for example) by the Washington Post? Jane Chong, at Lawfare, thinks at least maybe not, and indeed it is notable that Nunes' language is incredibly informal. How temporarily? What does “take charge” mean? This is an important practical question: for example, the HPSCI's Rules provide that subpoenas shall be authorized either by the "Chair of the full Committee, upon consultation with the Ranking Minority Member, or by vote of the full Committee." Does Nunes plan to authorize subpoenas related to the Russia investigation? Will he vote on whether they should be authorized?
Moreover, how exactly does the Ethics Committee plan to conduct its investigation into whether Nunes improperly disclosed classified information? The Committee says it will investigate pursuant to "Committee Rule 18(a)." That rule (as you can see for yourself on the Committee's website) provides that "the Committee may consider any information in its possession indicating that a Member, officer, or employee may have committed a violation of the Code of Official Conduct or any law," and that the chair and ranking member may "jointly gather additional information concerning such an alleged violation by a Member, officer, or employee unless and until an investigative subcommittee has been established." That is extremely open-ended and tells us, more or less, nothing about what is going to happen next.
As a 2016 CRS report explains, the Ethics Committee's investigations are conducted "either pursuant to authorization by the Chairman and Ranking Member, under Committee Rule 18(a), or pursuant to a vote by the Committee to empanel an Investigative Subcommittee (ISC)." The former, which is what they're doing with Nunes (for now), is more common, and even "those investigations that ultimately result in the formation of an ISC usually begin as Committee Rule 18(a) investigations.” So maybe this will result in an investigative subcommittee being empaneled. And maybe it won’t. Bryson Morgan, a former investigative counsel with the Office of Congressional Ethics, called a Rule 18(a) investigation "the black box of congressional ethics investigations": "You just don't know what you're going to get." We therefore have no way of knowing whether (for example) Nunes will be required to explain under oath how he came to learn the information that he disclosed, or whether (for further example) the President authorized him, either personally or through an authorized agent, to disclose it. That would seem highly relevant, given that the President can essentially declassify anything he wants, and so it could well matter if (say) someone acting on Trump’s orders told Nunes to do what he did.
Nunes' sorta-recusal was rightly overshadowed by the news that the United States conducted a missile strike against the Syrian government. But it will be of ongoing significance, both to the HPSCI's work on the Russia probe, to Nunes himself, and (potentially) to the public's understanding of this entire strange affair.