I've always believed the whole BC thing was a Hillary deal.
I think Biden would choose Hillary as VP were Obama to somehow be dis-qualified as President.
Besides Amendment 20, there was something else I read last week about all this & I can't find it now. I spent some time last night & then this morning looking for a link. But I read so many things from so many sources, some of it only opinion comments - it's hard to find again unless I specifically bookmark things on my computer. I like to provide a link when I comment on such things because I know the wingnuts will accuse me of making it up or subscribing to conspiracay theories. I don't.
That said, I remember reading something along the lines of - if the US votes to elect a person who is not legally qualified -and if that person is actually voted in by the Electoral College- (because he is not even the President elect until that is done) then there is some violation of the Constitution and we have no valid government since the Consititution is voided.
The information posted above from Amendment 20, section 3 applies before the inauguration. After the inauguration
Amendment 25 applies.
I'm only paraphrasing what I remember reading. I'll keep looking for it to see if I can post what it was. Whatever happens, I just find interesting the fact that a man who is going to be our future President feels it unnecessary to simply provide proof of his birth & quiet all this commotion once & for all.