From the San Diego Union Tribune:

... in effect, if a governor and attorney general were unwilling to defend an initiative approved at the ballot box, as in the case of Proposition 8, those two elected officials could veto the measure with their inaction.

Andrew Pugno, general counsel for the Proposition 8 Legal Defense Fund, said such a scenario would affect “any other issue decided by initiative, as well as the integrity of the initiative process itself.”

And from the other side:

Pizer added that [Lambda Legal] does not believe state law allows proponents [of an initiative] a seat in court battles.

One wonders if supporters of gay marriage would still hold to this position of denying voters standing in court if tables were reversed.