If the court rules that individual states can not determine eligibility the door would be open to all third parties for ballot access challenges.
The court would have to set up or help to establish federal rules to determine eligibility requirements or face a flood of challenges for all 50 states. That seems to be a nail in the coffin of Federalism.
A Trump victory in SCOTUS would set up a 50 state rush of indie candidates who would take eligibility questions to the high court. To avoid that they would have to legislate from the bench or convince Congress to legislate an end to Federalism!
That is the headline I expect to see post-election It's too early to see the full effect of the debate, but the most morose of the Commentary I have seen came from Democrats early after the event. It was that on which the pundit class based its commentary! It seems the only way media on either side of politics comments is Democratic self-loathing! The first ten things I read from the right this morning were the whimpering comments from the left about how they lost and needed to change course! Their self-deprecating made it as bad as they perceived! Tragically the debate was bad but not as bad as the dems made it out to be. It was one tiny data point in the face of a megalomaniacal cartoon-style villain, a felon with 34 felonies and multiple remaining felony indictments who incited an election overthrow to dispossess the votes of 81 million voters!