It’s great that the FBI is probing former CIA Director John Brennan’s role in the Russiagate conspiracy, but the country needs a lot more than criminal investigations and prosecutions to fully air the truth about the 2016 plot to smear Donald Trump as a pawn of Vladimir Putin.

The probe turns on Brennan’s apparent perjury in congressional testimony about one part of his role, namely the fact that in 2016 he ensured that the “Steele dossier” would be part of an Intelligence Community Assessment that claimed to find real Trump-Russia collusion.

The dossier, you’ll recall, was a farrago of fiction (including the “pee tape” lie) about Trump’s alleged connections to Russia; the Clinton campaign paid British ex-spook Christopher Steele to fabricate it as a weapon against Trump during the 2016 campaign. 

And now-declassified docs show that Brennan worked to amplify the lie by getting it into the ICA — which “mysteriously” leaked to the press, putting DC into a Russiagate fervor as Trump took office.

The lies kneecapped the Trump administration for years, until special prosecutor Robert Mueller’s report in 2019 admitted that it was all baseless.

A CIA “autopsy” of the ICA process found that Brennan’s “direct engagement in the report’s development was highly unusual in both scope and intensity” and “risked stifling analytic debate.” 

Yes: He overruled the agency’s top two Russia hands and other career officials to make it happen, allegedly even telling one underling who warned of the dossier was junk: “Yes, but doesn’t it ring true?”

This was a slow-motion coup attempt; it didn’t dislodge Trump, but crippled his early administration.

Brennan kept it up as a private citizen, milking his former high office as he retailed endless lies on the lefty cable news circuit, in The New York Times and in his 2020 memoir.

It’s also a safe bet that he was one of the anonymous “current and former officials” regularly cited in Times, Washington Post and other news accounts as reliable sources saying the feds had all manner of damning dirt about Trump and Russia.

Before and after Trump’s inauguration, many others abused their power to fan these flames: James Comey and others at the FBI; multiple Justice Department lawyers; Director of National Intelligence James Clapper.

All with some tacit approval, and sometimes active cooperation, from President Barack Obama.

The nation needs the truth of all this on the record — not to send anyone to prison, but to open eyes about how brazenly these insiders misled much of the country, wantonly abusing federal criminal-justice and national-security power for nakedly partisan purposes.

And yes, the shoe could be on the other foot next time, though Republicans couldn’t pull off exactly the same scheme, as they don’t have remotely enough partisans salted throughout the government or the media.

As important, Russiagate launched a longer wave of abuse: All the COVID-era deceptions and delusions, and subsidiary outrages like the suppression of the Hunter Biden “laptop” scandals, followed in train.

If America is to regain trust in its institutions, the public needs a full accounting of the abuses that led them to lose that trust.