Many Democrats expressed concern on social media over Robert Mueller's performance during his testimony in front of the House Judiciary Committee Wednesday morning.

Former President Barack Obama adviser and CNN commentator David Axelrod said that Mueller "does not appear as sharp as he was" when he testified in front of Congress six years earlier.

This is delicate to say, but Mueller, whom I deeply respect, has not publicly testified before Congress in at least six years. And he does not appear as sharp as he was then. — David Axelrod (@davidaxelrod) July 24, 2019

The former special counsel is testifying about his 448-page report released in March, in which he concluded that neither the president or his campaign knowingly conspired with Russia to win the 2016 presidential election. Despite that, Mueller did not rule whether or not the president obstructed justice, following a long-standing Department of Justice guideline saying a sitting president cannot be indicted.

During Mueller's testimony, he often had to have members of the House Judiciary Committee repeat questions and asked for further clarifications.

At one point when he was being questioned by Rep. Zoe Lofgren, D-Calif., and Mueller referred to the president as "Trimp," before quickly correcting himself.

Unfortunately for our democracy, Robert Mueller is not at the top of his game today. He just isn’t. Something is off. — Michael Avenatti (@MichaelAvenatti) July 24, 2019

Michael Avenatti, former lawyer for Stormy Daniels, Trump adversary and one-time 2020 Democratic hopeful, tweeted, "Unfortunately for our democracy, Robert Mueller is not at the top of his game today. He just isn't. Something is off."

MSNBC host Joy Reid said that Mueller looking "old and feeble" could help Democrats: "Lots of twitter folks are dogging Mueller out for looking old and feeble. But optically, that just makes the Republicans yelling at him look more absurd. Mueller is quite definitive in his one word answers, which only Dems are eliciting from him so far."

Lots of twitter folks are dogging Mueller out for looking old and feeble. But optically, that just makes the Republicans yelling at him look more absurd. Mueller is quite definitive in his one word answers, which only Dems are eliciting from him so far. — Joy Reid (@JoyAnnReid) July 24, 2019

Newsweek columnist and Trump critic Seth Abramson called Mueller "a bit of a bumbler as a witness," adding that his "answers sound hesitant and frail," in a Twitter thread.

17/ Oddly, Mueller being a bit of a bumbler as a witness is going to make it harder for the GOP to paint him as a villain. He... *really* doesn't come off that way. Cutting him off/yelling at him isn't going to make for good TV. That said, I could wish he were a stronger witness. — Seth Abramson (@SethAbramson) July 24, 2019

This is delicate to say, but Mueller, whom I deeply respect, has not publicly testified before Congress in at least six years. And he does not appear as sharp as he was then. — David Axelrod (@davidaxelrod) July 24, 2019