The CIA viewed reporting from Christopher Steele, a former officer of the CIA's closest foreign intelligence partner, as "internet rumor."

That's what we learn from page 178 of Justice Department Inspector General Michael Horowitz's report into the FBI's handling of investigations into the Trump campaign.

Horowitz observes that:

"According to the Intel Section Chief and Supervisory Intel Analyst, as the interagency editing process for the [January 2017 Intelligence Community Assessment into Russia's election interference] progressed, the CIA expressed concern about using the Steele election reporting in the text of the [intelligence community assessment]. The Supervisory Intel Analyst explained that the CIA believed that the Steele election reporting was not completely vetted and did not merit inclusion in the body of the report. The Intel Section Chief stated that the CIA viewed it as 'internet rumor.'"

This is a pretty big deal for two reasons.

First off, Steele was a former and well-respected Russia specialist at Britain's equivalent of the CIA, the Secret Intelligence Service, also known as MI6. Due to the extremely close cooperation between the CIA and MI6, we would have expected the CIA to view Steele's dossier as at least somewhat credible. That the CIA did not, and instead viewed Steele's dossier as unverified, unvetted, and rooted in "rumor," is a striking rebuke. Had the CIA been able to verify any significant measure of Steele's report, it likely would have supported including at least a corroboration source reference for any assertions in the intelligence community assessment. The "internet rumor" assertion indicates that the CIA was unable to do so, or unable to gain MI6's confidence for Steele's claims. In turn, that suggests MI6 did not regard Steele's dossier as credible.

Second, by its lack of confidence, the CIA is basically saying that it viewed the FBI's reliance on Steele as fundamentally misplaced. Not a great endorsement of the FBI's intelligence collection and assessment machinery.

At least by December 2016, the CIA viewed a former member of its top allied partner to be little more than a conspiracy theorist.