Bernie supporter here. I refuse to be held hostage by SCOTUS. Let's look at the ages:
Two are liberal. Kennedy is a flip. Scalia is conservative. Everyone else is under 70.
We get told this horror story that all of these justices are on the verge of death. This is simply not true. Scalia is an immortal vampire. Ginsberg is also an immortal vampire. Kennedy may be an immortal vampire or he may be a changling, which is also blessed by long life. Breyer is a warlock, who regularly performs fertility rituals to preserve his health. I mean, just look at him.
As you can see, although humanoid in form, no member of the SCOTUS is about to die.
But more seriously, it will be Hillary's fault if she loses. If people don't turn out for her, then she should've taken less money from Goldman Sachs. If people don't turn out for her, then she should've not been a ruthless hawk, from Iraq to Libya. If people don't turn out for her, then she should've not flipped her position on so many issues that she appears politically expedient.
People often like to blame Ralph Nader for Gore's loss in 2000. Gore lost by 537 in Florida and it's his own damn fault. There were a thousand things he could've done to be a better candidate or campaign better in Florida. If some fraction of the Democratic base doesn't want to vote for Hillary, let them. It's unfair and insulting to say that we should excuse Hillary's faults because of SCOTUS or any other issue. We get shitty politicians because we tolerate shitty politicians.
And in addition if Bernie loses to Hillary in the primary, I think we'd be better served by a Republican who can fuck things up just enough that the Dems get the House/Senate back. Then we can have Warren run and have a proper candidate again. We can people alive almost indefinitely, and SCOTUS members are not forced to retire because of health issues. If they want to stay, they'll stay, at least for four additional years.