Jerry Brown is too old (I still have buttons and bumper stickers from his 1972 campaign). Joe Biden is also too old. Hillary is pushing the limit.
Much as I like Obama, there’s reasons it would have been good for one of the old guard to take it in ‘08, while he did a stint as Illinois Gov to learn executiving lessons that he needed a year as president to really get a handle on. and ran next.
The Dem bench is sadly full of JV’s, it’ll be awhile before they have another great primary campaign.