I think it is a great suggestion... all politicians should be required to take a cognitive function test once they pass age 70. Let's throw Supreme Court Justices into that category and Federal judges.
Biden should do so first and then call on Congress to follow his example and to pass legislation that requires all Presidents and Congressional representatives past a certain age to take a test every two years. Roll in judicial members with lifetime appointments.
I mean many states have begun to require seniors to retake their driving tests... what is more dangerous someone with their hands on the steering wheel of a car or someone with their hands on a nuclear button.
Keep in mind, it is now suspected that Reagan's Alzheimer's began to impact him in his last two years of office. Is that really okay? Who elected a President's staff to run the country?
If a politician fails the cognitive test, they should resign or Congress act to remove them.
As an aside, I think the pushback in Congress will come from Democrats and not Republicans. The average age in Congress is 59-60 years old with the Senate several years older than the House. Party-wise Democrats on average are older than Republicans partially because of how their party rules work.
I don't believe in age discrimination and my comments are not political. I think Sanders appears to be "on his game" even at his age eventhough I am not a fan of his politics... but, Biden has issues and ignoring them is dangerous...
No one has so much power as the President of America, the world needs to know he or she is functioning at full capacity.