The fate of Proposition 19, which would legalize marijuana in California, is still very much up in the air. Depending on which most recent polls you look at, the measure is either winning by a few points or losing by a few points. Looking into the crosstabs of the polling on this proposition, it is clear that the success or failure of Prop 19 rides on the ability of its supporters to get out the vote.

According to the recent SurveyUSA poll, supporters of Prop 19 are more likely to be infrequent voters and less likely to have already voted by mail. The poll found those voters who say they “always” vote oppose Prop 19 by a margin of 44 to 47. On the other hand, likely voters who tend to rarely vote in midterms overwhelmingly support Prop 19. As a group, these infrequent voters support Prop 19 by a margin of nearly two to one, 58 percent to 34 percent. This means that for every two percent increase in overall turnout from infrequent voters, there would be an almost one percent increase in support for Prop 19.

The poll also found that among people who have already sent in a ballot, Prop 19 is narrowly losing, 47 percent to 50 percent, but it leads 48 to 42 among those who plan to vote but have not already. Of course, people who have already voted can’t change their minds and, by definition, can’t forget to vote on election day, which is not true with those who have yet to vote early.

So, with those who support Prop 19 generally more likely to be infrequent voters and more likely to have not voted early, the quality of the get out the vote operations in support of Prop 19 will likely be critical. The votes exist to pass Prop 19, but it includes many voters that don’t tend to show up for midterm elections. Being able to produce them could be the decisive factor.

The other interesting point in this data is that much of Prop 19’s potential support is among people who are probably not seen as “likely voters.” This means some pollsters might be overlooking these voters in their likely voter models, and so slightly understating Prop 19’s support. In general, the higher the overall turnout is in California on November 2, the better Prop 19 will likely perform. Watch for turnout as a good indicator on election day.