Presidential elections as they exist today are a special case since they are not mentioned in the Constitution and the actors with responsibility over the REAL presidential election (the one in December) are the 50 State Legislatures, to which the Constitution grants plenary power over the choice of Electors.
The Constitution specifically says that the electors are to be chosen in the manner specified by the state legislatures.
Electors chosen by any other manner are not Constitutionally qualified to even be called “electors”.
This was clearly a Constitutional issue, when a bunch of states sued because states were certifying people as “electors” when they clearly did not meet the Constitutional requirement to be certified as electors.
SCOTUS was dead wrong to refuse that case.