This is the first midterm election cycle since 2002 where any incumbents of the non-presidential party lost re-election.  The Democrats lost four such races.  In part this was because of their terrible treatment of Brett Kavanaugh.  Marc Theissen wrote last week in "Kavanaugh treatment gave Senate to GOP":

It cost Democrats their chance to regain control of the Senate. And it gave Republicans an expanded Senate majority that will allow them to confirm an even more conservative justice next time around.

. . .

None of that might have been possible had it not been for the Democrats’ horrific treatment of Kavanaugh. As Senate Majority Leader Mitch McConnell put it, the failed effort to stop Kavanaugh was “like an adrenaline shot” for the GOP base. Republican voters were outraged to see a good man accused, without a shred of corroboration, of sexually assaulting a teenage girl, exposing himself to a college classmate and participating in gang rapes in high school. They were disgusted by Senate Democrats’ insistence the burden was on Kavanaugh to prove he didn’t do it and by Democrats’ blatant disregard for the presumption of innocence. They were energized by Kavanaugh’s willingness to fight back and declare his treatment by Democrats a “national disgrace.” And they punished the perpetrators of that disgrace at the polls on Nov. 6. . . .

The lesson for Democrats should be clear: Character assassination does not pay. Quite the opposite, it backfired – big-time.

The next question is, will liberal groups pay any price?  One such group that should pay a heavy price is the American Civil Liberties Union.  As David Bernstein details in The Volokh Conspiracy:

To maintain its large membership base, the ACLU recruited new members by directing mass mailings to mailing lists rented from a broad range of liberal groups. The result of the shift of the ACLU to a mass membership organization was that it gradually transformed itself from a civil libertarian organization into a liberal organization with an interest in civil liberties.

The transformation from civil liberties to partisan liberal organization began during the George W. Bush Administration but was completed during the Kavanaugh hearings. 

First, the ACLU ran an anti-Brett Kavanaugh video ad that relied entirely on something that no committed civil libertarian would countenance, guilt by association. And not just guilt by association, but guilt by association with individuals that Kavanaugh wasn't actually associated with in any way, except that they were all men who like Kavanaugh had been accused of serious sexual misconduct. The literal point of the ad is that Bill Clinton, Harvey Weinstein, and Bill Cosby were accused of sexual misconduct, they denied it but were actually guilty; therefore, Brett Kavanaugh, also having been accused of sexual misconduct, and also having denied it, is likely guilty too.

Can you imagine back in the 1950s the ACLU running an ad with the theme, "Earl Warren has been accused of being a Communist. He denies it. But Alger Hiss and and Julius Rosenberg were also accused of being Communists, they denied it, but they were lying. So Earl Warren is likely lying, too?"

As Bernstein concludes:

The ACLU had a clear choice between the identitarian politics of the feminist hard left, and retaining some semblance of its traditional commitment to fair process. It chose the former. And that along with the Kavanaugh ad signals the final end of the ACLU as we knew it. RIP.