The FBI still has some explaining to do about the Steele dossier

Last week the Senate Intelligence Committee released a frustrating report for close watchers of the investigation into Russia's interference in the 2016 presidential campaign.

Yes, it affirms what most fair observers already knew: Four years ago, Russia meddled in U.S. politics on behalf of Donald Trump. Not only does the report say that the U.S. intelligence community's judgment was sound, but it also concludes that it was not based on a dossier of shoddy opposition research that the FBI used to obtain a surveillance warrant of a Trump campaign adviser.

At the same time, the report contains too many redactions to explain why the FBI's senior leadership wanted to include that dossier in the 2016 assessment in the first place.

The dossier, compiled by former British spy Christopher Steele and paid for by the Democratic Party, was far more important to the Trump-Russia investigation than many of the president's critics acknowledge.

For one thing, its claims were an important basis of the warrant applications the FBI submitted to electronically monitor a low-level campaign aide, Carter Page. In December, the Justice Department's inspector general gave a withering assessment of the bureau's handling of those surveillance warrants and then-FBI Director James Comey's pressure to include the dossier in the intelligence assessment.

After the Steele dossier became public in January 2017, it became a key element of the narrative that Trump had conspired with Russia to win the 2016 election and was possibly compromised by the Kremlin.

The Senate report provides some more context. It says that the FBI's assistant director for counterintelligence did not want the bureau to "stand behind" the dossier but that former President Barack Obama's directive was to "include all information" about Russian interference in the 2016 election. So, despite reservations about the dossier's accuracy, the bureau believed it had to include it.

There were good reasons to doubt the veracity of Steele's work. Earlier this month, the Justice Department declassified a series of footnotes from the inspector general's December report. They indicate that the FBI team investigating the Trump campaign knew in early 2017 that some of Steele's reporting was likely deliberate Russian disinformation. The report itself also notes that even some of Steele's sources wouldn't stand by his reporting.

Add it all up, and it's stunning that a team hand-picked by FBI senior leadership to investigate Trump and Russia would submit the Steele dossier to the secret surveillance court to obtain a warrant — and three subsequent renewals — or, for that matter, to the wider intelligence community as part an assessment of Russia's interference in the 2016 election.

The good news is that CIA analysts pushed back on the Steele dossier. The result was a compromise: A summary of Steele's findings was included in a classified annex to the assessment and briefed separately to both Obama and Trump.

Then CNN learned of this briefing, along with a dossier apparently important enough that both the outgoing and incoming presidents had to be told about it. Then BuzzFeed published the dossier in full. Then, for the next two years, the dossier drove the narrative about the Trump presidency — even as the FBI was learning that it was not reliable and may have been a product of Russian disinformation.