House Oversight Committee Chair James Comer, R-Ky., is investigating allegations that Biden's former top White House aides covered up signs of his mental and physical decline while in office, and whether any executive actions were commissioned via autopen without the president's full knowledge. Biden allies have pushed back against those claims.

A former senior aide to Jill Biden on Wednesday became the second person to invoke the Fifth Amendment and decline to answer questions from House Republicans who are investigating President Joe Biden’s mental state and use of the autopen while in office.