The Court might try to finesse the issue by ruling on the narrowest grounds they can find, allowing them to strike down Prop 8 in a way that does not set a mandatory precedent for other states.
Wasn’t part of Roberts’s argument on Obamacare that it is not the Supreme Court’s job to overturn the results of elections? The people voted for Obama and the Democrat House and Senate that voted in Obamacare so it should stand. The people of CA voted for Prop 8 so it should stand.