Joe Biden’s one-time personal physician, Kevin O’Connor, announced on Wednesday that he would take the fifth before the House Oversight Committee rather than discuss the former president’s fitness while in office. Republicans claimed this was evidence of a “cover-up”. Democrats dismissed the House inquiry entirely, insisting that Biden’s health issues were overblown.

Both are getting this wrong. Congress should thoroughly investigate whether Biden was physically and mentally capable of carrying out his duties — and not just to sate understandable public curiosity about the previous administration.

Biden’s case is only the latest evidence that lawmakers should take on the difficult but unavoidable topic of whether to set transparency rules on presidential health. This means Democrats cannot deny that the Biden health story is important. It also means the Republicans running the probe should be more interested in getting relevant information than in embarrassing Democrats. So far, neither side is looking great.

Reporting since Biden left office suggests he frequently forgot top aides’ names and needed to use a teleprompter even for minor events. His Cabinet meetings were scripted. He often struggled to keep up with the long hours the job requires, with O’Connor frequently recommending more rest. His aides also reportedly tried to hide his frailty from the public.

These reports raise legitimate concerns that Biden’s health threatened national security and continuity of government. Lawmakers have a responsibility to carefully examine the matter and use their findings to consider reforms that would preserve Americans’ confidence in their leaders.

Granted, O’Connor’s position is tricky. He has ethical and legal obligations to protect private patient information. He also fears that the Justice Department could use his testimony against him, after President Donald Trump directed it to investigate whether Biden aides “conspired to deceive the public” by hiding the former president’s health issues.

But O’Connor could probably reveal more than anyone else about how White House officials seek to control the public’s perception of a president’s fitness. He could speak to whether he ever felt pressure to sanitise his annual public reports on Biden’s health. He could discuss the process of writing those reports accurately while keeping the President’s trust. He might also offer insight on whether presidents should be subjected to more frequent or more extensive testing, given that Biden claims his late-stage prostate cancer was detected only after the 2024 election.

All of this would be useful information if Congress were to consider requiring presidents to reveal more about their health, such as by mandating that they undergo regular physical exams and cognitive testing by independent professionals.

In an ideal world, Republicans and Democrats would see this congressional inquiry as an opportunity to improve American governance rather than as an opportunity to score political points. They might form a bipartisan commission, staffed by serious thinkers in each party, to study the issue and craft recommendations to improve transparency about a president’s fitness.

But Democrats’ broad resistance to confronting Biden’s decline, and Republicans’ eagerness to use the issue against them, make it unlikely that Congress will perform such a useful service. Congressman James Comer, chairman of the Oversight Committee, refused O’Connor’s request to delay the hearing so terms could be negotiated that would allow him to answer questions without violating doctor-patient privilege. Comer should reconsider.

Writing bright-line rules on presidential health is hard, as is contemplating the related issue of whether some people are simply too old to serve. Leaders such as Winston Churchill ran their countries ably into their eighties. Yet health risks typically multiply in people’s later years. All the more reason to conduct a sober and unflinching investigation into Biden’s fitness — as the starting point for a larger reconsideration of what Americans should expect to know about their presidents.