After an up-and-down year of polling on the topic, a preponderance of evidence now weighs in favor of Californians supporting legalization, as the latest poll from Field Research, released on Sunday, shows Prop. 19 passing 49 - 42 percent. 

This follows a poll last week from North-Carolina-based Public Policy Polling, whose automated survey showed Californians supporting Prop. 19 47 - 38 percent.

Field's latest poll is the most significant to be released thus far, and here's why.

Field is probably the most respected polling firm in California, and, until today, its numbers had showed Prop. 19 failing. The last time Field polled on Prop. 19, in early July, the firm found Californians opposing the measure 48 - 44 percent. It looked then as if Prop. 19 would have quite a hill to climb.

At the same time, automated polls and internal surveys by the pro-Prop. 19 campaign had found that the measure was popular, and would pass. Survey USA, another automated polling firm, had shown legalization as wildly popular in April. The Public Policy Polling survey last week, while encouraging, came from yet another national, automated polling firm. While last week's news was encouraging to supporters of legalization, no live-interview poll had weighed in favor of Prop. 19's passage.

Now, Prop. 19 is considered to be popular by two recent polls with different methodologies.

Field Research has possibly been the most influential entity in the push to legalize marijuana in California. As national news outlets turned their attention to California's budget crisis and the troubling proximity of Mexico's drug war to U.S. borders, Field conducted a statewide poll in April 2009 asking whether a slew of means should be examined to confront California's fiscal armageddon. A stunning 56 percent of Californians thought legalization of marijuana was a good option.

The next month, Gov. Arnold Schwarzenegger said marijuana legalization deserved serious discussion. (Interesting side note: one of Schwarzenegger's enemies in the state house, Tom Ammiano, to whom the governor would pen an official letter in October, the first letter of each line spelling "fuck you," was the leading proponent of legalization in the legislature.)

The April 2009 Field poll, followed by Schwarzenegger's acknowledgement of legalization as a serious possibility, moved the paradigm on marijuana legalization. Before that, one didn't get the sense that it was taken seriously. But thanks to the findings of Field, as a respected institution, and the comments of Schwarzenegger, the state's Republican governor, legalizers were emboldened. Ultimately, Oaksterdam University (where they teach marijuana growing) founder Richard Lee decided to move ahead with the plan to legalize and put it on the ballot in 2010, against the advice of more staid voices in the national legalization advocacy community.

Now, a year and a half later, Field's methodology has weighed in again.

Prop. 19 looked unlikely, or at least borderline, until yesterday.