The SCOTUS also denied standing to the people of CA for a suit forcing their state-officers from abiding by the Prop 8 Amendment -- even though the CA Supreme Court certified their standing in the absence of the State's prosecutor taking up the case. In so doing, the USSC told the people that it is not a State matter.
So it very much seems that whether it's a State issue or not depends on if it's in line
with their opinion.
Imperial Courts