I doubt this surprises most Democrats. We always thought the FBI didn't really put much effort into investigating Kavanaugh after he was nominated to the Supreme Court (and accusations of sexual abuse were leveled against him). Did the FBI make their own decision to do only a cursory investigation, or were they following orders from the Trump White House? I suspect the latter.
The following is what Steve Been of MSNBC.com had to say about it:
Supreme Court Justice Brett Kavanaugh's confirmation hearings in the fall of 2018 were highly controversial for a variety of reasons, including the scope of the FBI background check that was supposed to be part of the process.
Two days before the Senate's confirmation vote, with the FBI review ostensibly complete, Sen. Susan Collins (R-Maine) said it appeared to be "a very thorough investigation." Nearly three years later, there's ample evidence to the contrary.
A group of Democratic senators is demanding more answers from the FBI after the agency revealed new details about the limited scope of its supplemental investigation into Brett Kavanaugh's background when he was a nominee for the Supreme Court. In a letter June 30 to Sens. Sheldon Whitehouse, D-R.I., and Chris Coons, D-Del., made public Thursday, Jill Tyson of the FBI's congressional affairs office acknowledged that the department conducted only 10 additional interviews in its supplemental investigation, even though it had received over 4,500 tips.
According to the FBI's Tyson, said "relevant tips" from phone calls and messages were forwarded to the counsel's office in the Trump White House.
To be sure, it's impossible to say with confidence how many of the 4,500 tips had any legitimacy, but the fact that "relevant tips" were directed to the White House raises questions about the volume and seriousness of the possible leads and how they were treated.
Just as importantly, NBC News' report added, "It's unclear what became of the tips after that."
The Washington Post's Ruth Marcus, who called the FBI review "laughable," made a compelling case against an incomplete process:
What did then-White House Counsel Donald McGahn do with the "relevant tips?" That, we do know: not a damn thing. McGahn had no interest in discovering what his handpicked nominee had done, or not done. He had every interest in ensuring that Kavanaugh be confirmed, facts be damned. If there was any follow-up within the FBI itself, there's no indication of that. And that is the outrage here. The FBI's investigation into sexual assault allegations against Kavanaugh wasn't designed to uncover the truth.
Donald Trump recently said, in reference to Kavanaugh, "I saved his life. He wouldn't even be in a law firm. Who would have had him? Nobody. Totally disgraced. Only I saved him.... I saved his life, and I saved his career."
It was a curious quote, which is now seen in a new light.