I think this conversation is one where there's polarized extremes being discussed and the answer is somewhere in the middle.
I answered 'yes' based on how the question was worded.
However, if the question was "is Biden to the degree of cognitive decline that it prevents him from being able to do the job?", then I'd answer 'no'
Basically, whenever this conversation comes up, I see people on both sides who make "blinders on" types of assertions.
You have one side claiming he's a bumbling fool who's declined so bad that he can't remember how to tie his own shoes (based on some selectively edited clips).
You have the other side who wants to reject the notion of cognitive decline so much so, that they'll honestly pretend that he hasn't declined at all, and is the same Joe of 2008-2012.
The guy's almost 80, it's silly to say that there hasn't been any decline...it happens to everyone as they get older.
The reality is (coming from the NIH)
10% of people over 65 will have at least some form of what they call 'age-associated cognitive impairment', and.
40% of people over 65 have at least some some form of 'age-associated memory impairment'
(and those numbers go up even more at age 75, 85, etc...)
However, that's not the same thing as a person having full-blown dementia.
Is it something that could get to the level of concerning in the next 3-4 years? Possibly. As someone who had multiple grandparents live well into old age, it seems to be different for everyone.
My grandpa lived to 86, started showing mild decline in his mid-70's, by 83, he had a hard time remembering which grandkid was which and would leave the stove on by accident.
My one grandma lived to 88, started having the mild decline in her 70's, but it never really got any worse than that...
My other grandma lived to 98, sharp as a tack right up until the very end.
In a nutshell, you have many on the right over-exaggerating the situation based on a facebook/youtube video they saw from Louder w/ Crowder, and many on the left pretending that it's not even a concern at all in efforts to rebuttal the right. I wouldn't call either an accurate assessment.