Is Joe Biden mentally fit to be running for President

Don't the biggest liars make the best politicians? Honest people can make more of a difference staying out of politics in my opinion. As for the arses already in there, I rarely care for any of them. My suspicion, giving the currently elected leaders in both the US and UK, is that anybody who's sane and able is unlikely to be voted in: after all, they have to be representative of the electorate, right?