Mueller's blunders were obvious before he testified

Washington Post:

A performance full of stumbles shakes a sterling Washington image

In what was likely to have been his final act on the national stage, Mueller’s halting testimony was at times painful to watch.

His biggest blunder was the failure to investigate the Russian collusion of the Democrats in the publication of a fraudulent document like the Steel Dossier with the help of Fusion GPS.  It was a smoking gun of Russian collusion by the Hillary Clinton campaign designed to attack the Trump campaign and also to be used as a reason for a coup attempt.  When asked about it Mueller seemed absolutely clueless as does much of the liberal media.  It looks as though Mueller's operation was a giant coverup of the real Russian collusion in the 2016 campaign.