It's all in the editing (and the understanding)

It's pretty funny to read how Right wing political punditry think the Mueller testimony was a disaster for Democrats (and it's true that quite a few on the anti-Trump side gave bad reviews to his performance as well), yet when you see on TV the key parts done as a 60 second highlight reel re-iterating the scandal that was the Russian interference, the welcome use by Trump of stolen emails, the lies of those around the campaign to cover it up, and Trump's trying to shut down the investigation, it doesn't look dire at all.  

Of course, others have made this point too:

As has been clear all along, this historic scandal is a case of Republicans gaslighting themselves about what went on and preferring fantasy Deep State conspiracy over reality.    All fed by their fawning to a President whose intense narcissism means that he cannot admit reality because he thinks it erodes the legitimacy of his narrow win.  (And in truth, it does.)

Republicans already look like fools - I can't imagine how bad they are going to look with the clear perspective of history.