In almost any other occupation I wouldn't worry about 78 being old.
I wouldn't even worry about 78 with a mild heart attack being too old.
With the office of POTUS however, the consequences of being sidelined by something that serious, are wide ranging and can potentially affect every man, woman and child on Earth.
So it's not that I think Bernie is too old, I think he's too old and frail, only for the job of POTUS. I think that he should finish out as many terms in the US Senate as he wants.
I even think that he should be a valued member of the incoming POTUS cabinet.
I'd even be okay with him being VP if paired with the right candidate.
And if by some miracle Bernie DOES WIN the Democratic Party nomination for POTUS, I WILL vote for him in November 2020, but unlike 2016, I won't support him in the primaries like I did last time around. My support goes to Liz Warren, who is clearly healthier.
It's not ageism...the man just had a heart attack.
I might (God forbid) have one just like his tomorrow, but I wouldn't dream of running for POTUS in the aftermath if I did.
If he gets the nomination, I will cast my vote for Bernie 2020 as POTUS but he is not my first choice and I would hope he would pick a more robust running mate, and I would worry about him surviving the job every single day he was in office.
Last time around I started off supporting Jim Webb, when he didn't campaign, I switched to John Kasich, before finally voting third party against both major party candidates. This time I started off supporting John Hickenlooper, he has withdrawn. Now I'm keeping an eye on Amy Klobuchar and Tulsi Gabbard. Although I don't have much hope for either. I like Joe Biden, always have. As a senator and as VP. But I do wonder if he isn't getting a bit senile. Perhaps his time has come and gone. Even so, if Biden gets the nomination, I'd vote for him. Especially if his VP would be Gabbard or Klobuchar.
I would much prefer the Democrats go with a fresh young face. Not with someone 70 or older. Time to pass the baton to a younger generation. Anyway, here is the latest from RCP. https://www.realclearpolitics.com/epolls...ation-6730.html
Staying with age, check out question 57 Ideal Presidential age - What is the ideal age for a person to serve as President of the United States?https://d25d2506sfb94s.cloudfront.net/cumulus_uploads/document/x3neaunoh2/econTabReport.pdf