Bruce Reed, former President Joe Biden‘s deputy chief of staff for policy, dismissed concerns about Biden’s mental acuity during his testimony to the House Oversight Committee for its investigation into the former president’s inner circle and his use of an autopen.

During the interview, Reed blamed Biden’s poor debate performance with President Donald Trump last June on the former president’s stutter, according to a source familiar. Reed also said the decision to hold the debate early had nothing to do with concerns about Biden’s age and was instead a tactic to “get ahead of early voting and the Olympics.”