Over the past month, support for Proposition 37 has sharply declined among California voters, according to results of the latest USC Dornsife/Los Angeles Times Poll.

The ballot initiative, which would require new labeling for food that contains genetically modified ingredients, currently garners support from 44 percent of California voters — a 17-point drop from the USC Dornsife/Los Angeles Times Poll conducted in September 2012. The latest poll shows that 42 percent of voters oppose the measure and 13 percent are undecided. In September, 61 percent of voters supported the measure, 25 percent opposed it and 13 percent were undecided.

As opponents of the ballot initiative have poured money into advertising against the measure — with funding levels of nearly 5 to 1 over their adversaries — proponents of the proposition have struggled to keep up.

“A term like ‘genetically modified food’ sounds very scary, so it’s not surprising that support for the measure was initially so strong,” says Dan Schnur, director of the USC Dornsife/Los Angeles Times Poll and director of the Unruh Institute of Politics at USC. “The challenge for the opposition has been to convince voters that there are economic consequences such as increased grocery prices to consider, and it appears that they are in the process of doing just that.

“But the most significant driving force behind this shift is the amount of money that the opposition has put into the campaign. When voters hear a message so much more strongly from one side than the other, it’s not surprising to see the poll numbers move like this,” Schnur says.

Video of Schnur and Los Angeles Times reporter Marc Lifsher discussing Proposition 37:

Support for Proposition 37 has also slipped significantly across party lines. Among registered Democrats, support has declined by 12 percentage points since September, with the initiative ahead 54 percent to 32 percent. Among registered Republicans, the initiative is lagging 30 percent to 58 percent (a decline of 19 points since September); and with “decline to state” voters, the initiative stands at 49 percent to 36 percent (down 14 points).

Younger Californians continue to support the measure more strongly than older voters, but their margin of support has also slipped since the September poll. Voters aged 18 to 49 support the initiative 55 percent to 35 percent (down 11 points since September); voters 50 and older now oppose the measure 36 percent to 49 percent (a decline of 20 points since September).

Support for the ballot initiative has dipped among both men and women: Men now oppose the measure 40 percent to 48 percent (previously, males supported it by 54 percent to 32 percent). Women support the initiative 49 percent to 37 percent; however, the margin has tightened significantly since September, when females supported the measure 67 percent to 19 percent.

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