Republicans have been massively underselling Biden as a demented disabled person who can barely speak or walk. It works until voters actually see him

And they see person who speaks better than Trump (2020). Trump (2016) was MUCH better. So when people see Biden speaking well like at the townhall or in the first debate where he did fine, Trumpists have to concoct weird ass theories of magical wonderdrugs that no one has heard of to explain the discrepancy. Does all of this actually fool anyone? Yes and no. It initially works only those who haven’t actually seen Biden. But it doesn’t work on average voters, who have a sort of understanding that if you had dementia and were truly frail there’s no drug to help you at this level, not even illegal ones.