After California's failed Proposition 19 initiative in 2010, marijuana legalizers are optimistic about two new ballot measures in Colorado and Washington.

At least three states are likely to vote on marijuana-legalization initiatives in 2012, but the measures in Colorado and Washington - two states with legalized medical pot and some permissive local laws - may stand the best chances of succeeding, having already qualified for the respective November ballots.

"These are going to be serious campaigns," said Ethan Nadelmann, founder and executive director of the national drug-policy reform group Drug Policy Alliance. "Each one has a decent shot of becoming the first state in the country to embrace this policy change."

Those who support legalization  got their hopes up briefly in 2010. A  late-September poll by Field Research showed Proposition 19 winning in California, after an election cycle that saw pot become almost mainstream as a political topic. Marijuana was aided by California Gov. Arnold Schwarzenegger's call for discussion of legalized pot in 2009, along with positive polling and the call by Rep. Loretta Sanchez, D-Calif.,  for legalization in response to the drug war. Suddenly, pot seemed to go from a social taboo to reasonable fodder for policy discussion.

Proposition 19 failed 46.5 percent to 53.5 percent.

In Colorado and Washington, however, the measures have more momentum.

Backers of Washington's I-502 initiative, to tax and regulate the production and sale of marijuana statewide, have already raised $1.2 million since the beginning of their signature drive in 2011. In Colorado, the campaign for a similar initiative says it has attracted hundreds of thousands of dollars through Marijuana Policy Project, a national pot-legalization group.

"We're just about to buy about $600,000 worth of TV for the fall," said Mason Tvert, co-director of the Campaign to Regulate Marijuana Like Alcohol, which is pushing the initiative. Those will follow the TV ad shown below, which ran  on Mother's Day, featuring a purported daughter emailing her mother to explain a conversion from college binge-drinking days to more mature, adult pot-smoking. ("I hope this makes sense, but if not, let's talk," the narrator proposes , thoughtfully.)

Mother's Day pot greetings aside, the 2012 campaigns have some major advantages over Proposition 19. The money is coming earlier, thanks in part to the wholehearted backing of the national marijuana establishment. In 2010, the pot gravy train was late pulling in.

Another advantage: The presidential-election year. Proposition 19's progenitor, Oakland-based marijuana entrepreneur Richard Lee, of Oaksterdam University, jumped ahead of conventional pot-political wisdom by spending millions of his company's dollars to qualify Proposition 19 in a nonpresidential year, casting his lot with buzzkilling midterm voters - in the year of a Tea Party wave, no less.

"Bringing this issue before voters in a presidential year guarantees better turnout in terms of demographics that support this issue," said Alison Holcomb, who heads the Washington ACLU's drug-policy program and is "on loan," as she puts it, as an in-kind political contribution to run the New Approach Washington campaign behind I-502.

Legalizers claim that private polling looks sunny in Colorado and Washington. "There's a modest majority in favor, but it's not a substantial margin," Nadelmann said, and a slew of minor public polls, not considered reliable by ABC News, have bolstered the confidence of organizers.

But marijuana faces an uphill climb, and as Proposition 19 showed, voters could sour on the notion of drug legalization in the final weeks of a campaign; polls in spring and summer, even reliable ones, don't mean voters will support ballot measures in November.

A Los Angeles Times poll this month showed that 50 percent of Californians oppose marijuana legalization, while 46 percent support it, mirroring Proposition 19's Election Day vote share. Then again, an October Gallup poll clocked national pot-legalization support at a record-high 50 percent, eclipsing opposition for the first time.

Former New Mexico Gov. Gary Johnson, the pro-legalization Libertarian Party presidential candidate, predicted in early 2011 that marijuana legalization was two years from a tipping point, when politicians like himself could openly discuss its policy merits and actually get elected. National surveys have trended in advocates' favor, but results haven't shown it at November polls. The two 2012 initiatives will at least supply another reference point.