The House Oversight Committee is demanding a top aide to Jill Biden come in for questioning about President Biden’s mental fitness and his staff’s use of the autopen. The aide, Anthony Bernal, has worked for the former first lady for nearly 20 years. 

The chairman of the committee, Congressman James Comer, has been the face of several congressional investigations into the 46th president and his family. Mr. Comer led the probe into allegations of an “influence-peddline scheme” among members of the Biden family, which eventually culminated in a failed impeachment inquiry. 

Mr. Comer says it is his responsibility to find answers about the former president’s mental fitness and the alleged coverup of his decline so that nothing similar can happen in the future. 

“The Committee seeks information about your assessment of and relationship with former President Biden to explore whether the time has come for Congress to revisit potential legislation to address the oversight of presidents’ fitness to serve pursuant to its authority under Section 4 of the Twenty-Fifth Amendment or to propose changes to the Twenty-Fifth Amendment itself,” Mr. Comer writes in a letter to Mr. Bernal. 

The chairman says Mr. Bernal must appear for testimony on July 16. Mr. Comer previously told the Sun that if aides fail to comply with his subpoenas, he will issue criminal referrals that he believes will be taken up by Attorney General Bondi. 

Mr. Bernal began his work for the Bidens in 2008, after President Obama tapped Mr. Biden as his running mate. In the following years, Mr. Bernal worked as a speechwriter for the then-vice president, as a deputy chief of staff for Mrs. Biden when she was second lady, and as her personal aide after they left the White House. 

He served as the first lady’s chief of staff for the four years of the Biden administration, and even attended Hunter Biden’s criminal trial in Delaware alongside most other members of the first family. Mr. Bernal now works as chief of staff at Mr. Biden’s personal, post-presidential office. 

Mr. Comer invited Mr. Bernal to come in voluntarily for an interview, though on Wednesday Mr. Bernal’s attorneys said he was declining to appear. 

“It’s abundantly clear that Anthony Bernal — Jill Biden’s so-called ‘work husband’ — never intended to be transparent about Joe Biden’s cognitive decline and the ensuing cover-up,” Mr. Comer said in a statement after Mr. Bernal said he would not show up for an interview. “Mr. Bernal is now running scared, desperate to bury the truth.”

Mr. Bernal was subpoenaed to appear for testimony before the Oversight Committee last year, though the Biden White House invoked executive privilege and declined to make him available for testimony. President Trump’s staff now says that Biden aides are not permitted to invoke such a privilege.

Mr. Trump’s deputy counsel said in a letter Tuesday that another Biden aide, Neera Tanden, did not have the right to invoke executive privilege because “subjects include your assessment of former President Biden’s fitness for the office of the President and your knowledge of who exercised executive powers during his administration.” The White House said that it was in the “national interest” that Ms. Tanden be transparent in her testimony. 

After his Tuesday interview with Ms. Tanden, Mr. Comer said that she had testified that she had “minimal interaction with President Biden” despite having “tremendous authority” as White House staff secretary. 

“She explained that to obtain approval for autopen signatures, she would send decision memos to members of the President’s inner circle and had no visibility of what occurred between sending the memo and receiving it back with approval,” Mr. Comer said. “Her testimony raises serious questions about who was really calling the shots in the Biden White House amid the President’s obvious decline.”