It's Not Normally The Defence Which Makes That Argument.

https://news.sky.com/story/joe-biden-still-fit-for-duty-at-81-doctor-says-despite-president-avoiding-cognitive-test-13083336

https://twitterwithbraincells.blogspot.com/2024/02/therell-have-to-be-committal-hearing.html

Not that anyone would find that expert witness particularly credible.

https://www.nytimes.com/2023/04/25/well/live/biden-president-age-health-2024.html

https://abcnews.go.com/Politics/lesion-removed-bidens-physical-cancerous-white-house-doctor/story?id=97617868