“This is delicate to say, but Mueller, whom I deeply respect, has not publicly testified before Congress in at least six years,” David Axelrod, the top strategist in Barack Obama’s campaigns, wrote on Twitter. “And he does not appear as sharp as he was then.”
In the little bit I watched, it seems 1) he desperately did not want to be there and 2) he desperately wanted to give no one sound bites. He seemed to be working extra hard to parse everything. I can imagine that combination makes it tough to come across like a Winston Churchill.