A lot of people here think she needs to be on the ballot before the convention.
I disagree.
Scenario: The convention cannot agree on a candidate. Unanimously asks Hillary to run. GOP protests she was not on the ballot. DNC points to Lautenberg in NJ as precedent that there HAS to be a representative from the other party on the ballot to make it fair. Cases start for the Supreme Court but takes longer than the election, so is moot.
She runs, she wins (Massive voter fraud and counting), Supreme Court never sees the original case.
A party's nominating process isn't really open to much of a legal challenge anyway ... unless someone like Kamala Harris wanted to come forward and claim that the DNC dumped her because she's black.