Rick Hasen (Election Law Blog) notes that "it seems very likely an initiative overturning the decision through a constitutional amendment will qualify and appear on the November ballot" (see here) and opines:

This helps John McCain because those conservative voters may not have come out in great numbers for him, but they will come out now to vote for this amendment, and they are more likely to vote for McCain than for the Democrat once they are already voting. That's not to say that California will go red, but it is to say that the Democratic nominee will have to devote more resources to this very expensive to campaign in state.