I'm surprised they even want anything to do with this. I don't there is a decision they can make that won't piss off half the country no matter what.
If they decide states have a right to control who can be banned from running in an election, then there is a clear pathway for states to ban anyone who does not align with their views from being on a ballet - See: Missouri Secretary of State stating Biden will be banned if the bans against Trump stand. Tit for tat becomes the standard.
Or if the decision is to say states don't have the right to ban a obviously evil candidate, then there is no pathway to prevent evil from winning.
Or if they say this ONLY applies to Trump, then evil wins again and open violence becomes a very real risk.