I don't know, but I think the "single justice" rule only pertains when the petition is an "emergency" seeking an immediate order.
Petitions for cert are discussed by the entire court, and each week it is in session, SCOTUS publishes a list of cases taken and rejected. If four SCOTUS justices agree to take the case, cert is granted.
With the usual flow of elections being unimpeded (allowing unqualified candidates to achieve a high degree of electoral success), there is zero pressure for SCOTUS to take the case.
The rule of law is secondary, always.
Each case is first previewed by a jurist who makes a recommendation on the certain denied It was the two cases I mentioned that were held before it could be denied.
If I still had my old computer I could tell you which two.
Dad explained it was a common practice when similar cases were coming before the court to make one decision effecting all of them.
Thus eliminating numerous hearing and hearing one large argument encompassing all.