Gov. Jerry Brown speaking to a Jewish congregation in Los Angeles earlier this week. (Alan Mittelstaedt/Neon Tommy)

Gov. Jerry Brown must offer broad doomsday scenarios, energize young voters to turn in their ballots by Nov. 6 and convince the eight percent of voters undecided on how to vote on his Proposition 30 tax increase proposal that money raised from higher sales and income taxes will be well spent, results of a new USC Dornsife/L.A. Times show.

Prop 30 would raise the sales tax statewide by a quarter-cent -- enough to raise the cost of the cheapest iPhone 5 by 50 cents -- and raise the income tax rates assessed on people making more than quarter of a million dollars.

Among registered voters, support for Prop 30 has slipped during the summer according to the USC Dornsife/LAT poll. A poll released last week by the Public Policy Institute of California showed no change in support during the summer.

But 77 percent of 18-to-29 year-olds registered to vote support from Prop 30. If the measure fails to pass, school districts have said the school year would have to be shortened, the University of California has said it would raise tuition and the California State University system has said it would admit fewer students. Making sure other demographics hear similar messages -- the threat of cuts -- is key to Prop 30's success.

(Also see: Prop 30 Vies For Attention Among Voters)

Brown's own support has been declining among independent voters, which a pollster called a red flag.

"This is the third straight poll were his disapproval has gone down with them," said Dave Kanevsky, Research Director of American Viewpoint. "It could be tipping point. He still is in a good shape overall, but he's being kept afloat by Democratic coalitions and the stronger disapproval for the Legislature. At some point you have to start wondering if the mess in Sacramento and the Legislature starts dragging down his approval as well."

(Also see: Prop 38 Rouses The Latino Vote)

Prop 30 is going up against Prop 38, an initiative from Pasadena attorney Molly Munger that would increase income taxes across the board. She's said her proposal is more fair to taxpayers since Prop 30's sales tax increase has a larger effect on low-income individuals and families.

But Prop 38 has been unable to attain majority support in polls.

"It is fairly rare to see an initiative increase its support in the last weeks of the election," said Dan Schnur, head of the USC Unruh Institue of Politics. "There's no historical precedent for a comeback by 38."

(Also see: Prop 30 vs. Prop 38)

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