While it has been known that the late Sen. John McCain (R-AZ) had given the Steele dossier to former Director James Comey, the IG report confirms that, explains how that came about and how McCain got the information to the FBI even after the FBI had already cut ties with Christopher Steele and found him to be unreliable.
What had been unclear was the timing and why McCain would have to pass on part of the Steele Dossier if the FBI was communicating with Steele.
But the answer is that they had officially cut off contact with Steele in October allegedly because he had been leaking to media. The IG report reveals that McCain then acted as conduit to get five additional “election reports” from Steele that the FBI had previously not been given, to the FBI on December 9, 2016. It is unclear if McCain knew that Steele had been officially cut off by the FBI.
According to the IG report at page 175-176, a McCain Institute staff member who has previously been identified as David Kramer met with Steele and got the reports directly from Glenn Simpson, the Fusion GPS head, a known opposition research firm and the firm who had been hired by the DNC and the Clinton team.
Several weeks later, on December 9, 2016, Senator John McCain provided Comey with a collection of 16 Steele election reports, 5 of which Steele had not given the FBI.  McCain had obtained these reports from a staff member at the McCain Institute. The McCain Institute staff member had met with Steele and later acquired the reports from Simpson. Steele told the OIG that a former European Ambassador to Russia who generally was familiar with Steele’s election reporting informed Steele that the former Ambassador would be meeting with Senator McCain at a conference in Nova Scotia in November, and asked Steele whether he wanted the former Ambassador to talk with McCain about the election reporting. Steele said he replied that he did, which resulted in the McCain Institute staff member visiting Steele in Europe in late November. According to deposition testimony the McCain Institute staff member provided in foreign litigation, during this visit Steele discussed his reporting with the staff member and showed the staff member a piece of paper on which Steele had written the true names of his sub-sources, although the staff member could not recall them. Steele told us that he shared some of the sub-source names with the staff member because the staff member was a “Russia expert” and had been tasked by Senator McCain to determine whether Steele’s reporting was serious. The staff member also testified that Steele explained to him that the information in the reports needed to be corroborated and verified and that Steele was not in a position “to vouch for everything that was produced…. ”
Additionally, as we detail in Chapter Nine, on December 10, Department attorney Bruce Ohr received a thumb drive from Simpson containing some of Steele’s election reports and provided the thumb drive to the FBI.  Included among the reports on the thumb drive was a document that the Crossfire Hurricane team had not previously seen, which recounted that a senior official in the Russian Ministry of Foreign Affairs had reported that a rumor was circulating that President elect Trump’s delay in appointing a new Secretary of State was the result of an “intervention” by Putin and the Kremlin, and that they had requested Trump appoint a “Russia-friendly” figure who was prepared to lift sanctions against Russia.
According to Fox News, Kramer testified in a deposition:
[I]t was the sense from Fusion GPS founder Glenn Simpson that “having Senator McCain provide it to the FBI would give it a little more oomph than it had had up until that point.”
“I think they felt a senior Republican was better to be the recipient of this rather than a Democrat because if it were a Democrat, I think that the view was that it would have been dismissed as a political attack,” he said.
It is perhaps not coincidental to note what else was going on at this time in December 2016 and why there might be a rush by Simpson to get the information to the FBI/DOJ. It was literally their last opportunity to stop Trump from becoming president, albeit a long shot.
At this point, yes, Donald Trump had won the election. But Democrats were doing all they could to try to influence electors, who were theoretically committed to Trump, to vote otherwise on December 18. And as we recently reported, the Clinton team was actually supporting a “bipartisan” letter from ten electors requesting to have all the electors briefed on Russia interference allegations before they voted. That quite likely would have included the dossier, if it had happened, since it was included in the appendix of the ICA in January 2017 that was given to Trump. The ten electors, one Republican and nine Democrats, included Rep. Nancy Pelosi’s daughter, Christine, who wrote the letter and seemed to have a lot of information, even naming Carter Page in the letter. Fortunately, that didn’t happen.
Supporters of McCain later argued that he only did what one should do by giving the information he received to the FBI. But Kramer then passed the information on to Buzzfeed who published the unverified dossier at the end of December. That’s a little harder to argue away than apprising authorities.