No fewer than a baker's dozen polls have surveyed Golden State voters since May of this year, and at least one more will appear the weekend before election day. The average for all the polls so far has Prop 19 winning 47.4%, with 43.2% opposed and 9.4% undecided.
The numbers would have been better for Prop 19 except for Monday's Reuter/Ipsos poll, which bucked the trend to show Prop 19 losing by 10 points. It is one of only three polls that show the measure losing; one was a Field Poll in July and the other was another Reuters/Ipsos poll in June.
Here are the results of the 13 polls, beginning with the most recent:
|10/03/10||Public Policy Institute of California||52.0%||41.0%|
|05/26/10||Greenberg Quinlan Rosner (D)||49.0%||41.0%|
|05/16/10||Public Policy Institute of California||49.0%||48.0%|
"What is remarkable is that the polls agree so closely," said Jay Leve, CEO of SurveyUSA. "Initiatives are among the most difficult things for pollsters to poll, because many of them are about arcane things that nobody knows about, like 30-year bond issues, so the polls can be all over the place. But in this one, the issue is pretty clear, and that's reflected in the agreement among the polls."
"Our surveys get more accurate the closer we get to election Day," said Mark DiCamillo, director of the Field Poll, which had Prop 19 trailing by four points in July, but leading by seven in September. "In our second survey, we were able to read voters the actual ballot question," he noted.
Field will be taking one more poll before the election, DiCamillo said. "We will release our final poll the weekend before the election," he announced. "It will be much more insightful."
But with less than a month to go, things are looking pretty good for Prop 19. Liberals, Democrats, and young voters consistently showed strong support for Prop 19 across all the polls, suggesting, somewhat paradoxically, that voters motivated by support for Prop 19 could help the campaigns of Democrats gubernatorial candidate Jerry Brown and Sen. Barbara Boxer, both of whom have come out in opposition to legalization. Likewise, if surging Brown and Boxer campaigns bring out Democratic and liberal voters, they are going to be likely to vote for Prop 19 despite the positions of their gubernatorial and senatorial candidates.
But Republicans, who oppose Prop 19 by margins of 2-1, are also counting on a massive turnout. If the primary is a reliable indicator, they could see just that. In 2008, Democrats made up 42% of the electorate and Republicans just 30%, but Republican enthusiasm this year could close that gap. In the primaries, where only 33% of the electorate voted, 44% of Republicans did, while only 32% of Democrats did. A strong GOP turnout combined with weak turnout among Democrats could spell doom for the measure.
If polling for some groups has been consistent, that hasn't been the case for others, especially black voters. For example, at one point, the Field Poll had Prop 19 losing by 12 points among black voters, while just weeks later Public Policy Polling had it up by 36 points. Black voters only account for 6% of the state's electorate, so the results may suffer from too small a sample size.
Pollster Nate Silver of Fivethirtyeight.com had another possible explanation, one he called the "Broadus Effect," after one Calvin Broadus -- better known as the rapper and major pot aficionado, Snoop Dog. It's a variation on the "Bradley Effect," named for former Los Angeles Mayor Tom Bradley, who lost a mayoral race despite leading in the polls before election time.
The "Bradley Effect" posits that polls can be skewed by respondents who reply with what they think are the politically correct answers, rather than what they really think. Silver noted that automated robo-phone polls were showing higher support among blacks than polls done with human poll-takers.
"This might also explain why the split is larger among black and Hispanic voters," Silver wrote. "Marijuana usage is almost certainly more stigmatized when associated with minorities, and drug possession arrests occur much more frequently in minority communities. This is in spite of the fact that rates of marijuana consumption are only a smidgen higher among blacks than among whites, and are somewhat lower among Hispanics."
Pollsters are congenitally cautious about making predictions on actual election results, but both DiCamillo and Leve made heavily hedged predictions. "Usually, the burden of proof is on the proposition," said DiCamillo. "It's always on the yes side to make its case. In this case, there is a lead, but it's not quite at 50% plus one. Most initiatives do get a few percentage points out of the undecideds, so you'd expect this one to be favored for passage, but it's not a slam dunk."
Undecideds would have to break dramatically toward a no vote for the initiative to lose if the poll average today holds until Election Day. With Prop 19 at nearly 48% and undecideds at just under 10%, it would need to pick up just better than one out of five of those voters to get over the top.
And DiCamillo says Prop 19's prospects are good, barring some sort of October surprise. "If somebody came in and started advertising heavily against it, that could change things," he warned. So far, there's been no sign of that, but there is still time for a late TV ad campaign.
SurveyUSA's Leve was only a bit more definitive. "That it's maintaining a 10-point lead is good for the initiative, but that it's having trouble getting that 50% plus one is not," said Leve. "It's sort of a glass half full thing. If I was in Las Vegas and I was a betting man, I'd bet on it to win," said Leve. "But I'd only bet money I could afford to lose."
With less than a month out Prop 19 is leading by an average of more than four points. A historic victory for marijuana legalization may be coming into view, but Election Day will be a nailbiter, and its going to depend on turnout and those undecideds.