Collectively, the polls show a double digit lead for Clinton over Obama in California. Yet a recent Gallup survey goes beyond the standard numbers and offers estimates based on a high versus low turnout and more importantly, based on the certainty of respondents as to their vote preference. The results show that there is still time for Obama to make up the difference on Clinton among undecideds. From the Gallup survey:

Clinton leads Barack Obama by 12 points to 18 points, depending on turnout assumptions. John Edwards languishes much further behind.

About a fifth to a quarter of Democratic voters say they may still change their minds about their vote choice. Among those who claim to be certain of their choice at this time, Clinton still wins, but by a diminished margin [only 8 points in a high turnout election.]