Trump vs. Biden: Who's Least "Mentally Fit" To Be President?

According to a CNBC/Change Research poll, most voters in six swing states don't consider either Trump or Biden as 'mentally fit' to be president. But can anyone be mentally fit to do the impossible? The US Presidency has been warped into something it wasn't ever intended to be. The President was never intended to try to "run" America, let alone the entire world! Both are impossibilities, and no degree of 'mental fitness' can make either one possible.