Warren leaves office at age 79 in 2029, teeing off the VP to carry on to the next race.

Obviously this is total wishcasting, and I think winning 2020 would have been very tough if Dems won 2016, but Dems winning 2016 would surely have prevented a two term Trump situation

She picks a dynamic younger VP who has more "back of the classroom" energy to balance her professorial persona. Moore, Whitmer, or Newsom come to mind. Age does become a factor in the race, and she commits to one term. They win in a tight race amid the anti-incumbent wave

let's say that Kaine/Warren win again and Kennedy/Breyer retire if they didn't do so already, creating a 6-3 liberal majority on the court. Inflation is still a thing, but there's no senility to allege of the President. Warren, at age 75, is the 2024 nominee

Now with the Scalia and RBG SCOTUS seats filled by Kaine (5-4 liberal SCOTUS), he runs for re-election in 2020 as the incumbent 62 year old president. Covid happens, but hopefully a better managed pandemic response means less of a swing against the incumbent. tossup result?

with Kaine as a popular VP at the top of the ticket in '16 it could have tipped the scales in PA, WI, and MI to prevent a Trump victory. Who would be Kaine's VP? A woman from the Senate, most likely. Warren makes sense, considering what was happening in 2016