Alex Nabaum

In nearly every crime-caper movie there’s a shifty guy on the street corner who, seeing the cops in hot pursuit, flips over a fruit cart to slow them down and give the culprits a chance to get away.

In Trump-era Washington, that role is being played with impressive conviction by Devin Nunes, the eight-term Republican representative from California and chairman of the House Intelligence Committee. Mr. Nunes, supported by a rotating coterie of conspiracists in Congress and the usual suspects on right-wing cable news, has labored to divert attention from the expanding Russia investigation by tossing out sinister-sounding allegations of wrongdoing by federal law enforcement officials.

Mr. Nunes’s act has kept alive the prospect of impeding or ending the investigation even as President Trump has backed off his efforts to fire the man in charge, the special counsel, Robert Mueller.

Last year he accused top Obama administration officials of improperly “unmasking” Trump associates in intelligence reports — a charge that turned out to be baseless. No matter: The whole point of this game is to make the job of the actual investigators harder while confusing the public about where the true scandal lies.

For the past week or so, Mr. Nunes — who supposedly recused himself from the Russia inquiry last April — has been dangling something even juicier: a classified memo by the committee’s Republican staff that is said to allege that the investigation was corrupted from the start by law enforcement officials intent on toppling Mr. Trump. In the heat of the 2016 presidential race, the memo reportedly claims, the F.B.I. tricked the Foreign Intelligence Surveillance Court into issuing a warrant to spy on the Trump campaign.

Sounds pretty serious! One would assume Mr. Nunes, who has previously appeared very concerned about the improper handling of classified information, would do all he could to protect any potentially sensitive material from public exposure. Yet he is refusing to show the memo to the Justice Department or the F.B.I. — an “extraordinarily reckless” approach, as Assistant Attorney General Stephen Boyd, a Trump appointee, wrote in a harsh rebuke to Mr. Nunes on Wednesday. “We do not understand why the committee would possibly seek to disclose classified and law enforcement sensitive information without first consulting with the relevant members of the intelligence community,” Mr. Boyd wrote.

He added that neither Mr. Nunes nor most of the committee members had even seen the highly classified materials on which the memo appears to be based — and the release of which could be damaging to national security.

Democrats have called the memo “profoundly misleading” and have said its factual allegations are taken out of context. They have prepared their own classified memo addressing the origins of the warrant, which they say was properly sought and approved.

But even if Mr. Nunes’s memo never sees the light of day, it has done its job — spawning a new wave of conspiracy theories as well as suspiciously timed calls to #ReleasetheMemo amplified across social media, many coming from what a German Marshall Fund tracking project found to be part of Russian-linked influence networks.

Mr. Nunes is not alone in trying to change the subject to anything other than Mr. Trump and the Russians. Thanks to some intrepid Republicans in Congress, America learned last week that the F.B.I. is harboring a “secret society” dedicated to destroying Mr. Trump. The proof? A text message using that phrase that was sent between Peter Strzok and Lisa Page, F.B.I. employees who worked on the Russia investigation and who, like roughly 65 million other Americans, expressed horror at the thought of Mr. Trump becoming president. On Tuesday, Senator Ron Johnson, a Wisconsin Republican, said the society’s existence was corroborated by an “informant” — by which he probably meant his Twitter feed. On Thursday, he admitted what reasonable people everywhere had already surmised — that the reference to a “secret society,” in the context of the full message, was a joke.

Putting aside the irony of members of the law-and-order party delusionally attacking America’s law enforcement community, Mr. Nunes and his ilk are causing real and possibly lasting damage for nothing more than a short-term political win.

It must be frustrating to be a Republican in Congress these days. For years, the G.O.P. has been flogging supposed conspiracies and scandals, from Benghazi to Hillary Clinton’s email server to systemic corruption at the highest levels of the nation’s law enforcement community. Now, at last, a real conspiracy comes along, setting off an actual federal investigation by veteran law enforcement officials and leading to multiple indictments and guilty pleas — and it’s aimed at their own man.