California progressives have plenty of reasons to go to the polls on November 2. In the governor’s race, Democrat Jerry Brown is locked in a dead heat with corporatist zealot Meg Whitman. Longtime reformer Barbara Boxer is battling Palin favorite Carly Fiorina for her Senate seat. And climate change deniers, in league with out-of-state oil companies, are gunning for a proposition to suspend a landmark greenhouse gas emissions law.

But Golden State voters who aren’t satisfied with merely beating back GOP challenges can take heart in the chance to support Proposition 19. The ballot initiative would make it legal for Californians over 21 to possess and cultivate marijuana for personal use, and would authorize local governments to regulate and tax commercial production and sales. Its passage would signal a major victory in the war against the "war on drugs."

The case for Prop 19 can be made with just a few stats. Between 1999 and 2009, nearly 570,000 residents were arrested for misdemeanor pot possession (plus another 155,000 who faced more serious felony charges). Harvard economist Jeffrey Miron, a prominent libertarian, estimates the annual cost of enforcing prohibition in California at $1.87 billion. But for all the time and resources the state has pumped into targeting these nonviolent, low-level offenders, there has been no corresponding drop in reported use.

There has, though, been a spike in racial disparities. Black adults across the state are arrested for pot possession at higher rates than whites—sometimes by a factor of three or four. The same ugly imbalances apply to black youth, even though their white peers are more likely to inhale. Pot arrests in California don’t often lead to prison, but the long-term consequences of a criminal record are severe and disproportionately burdensome to minorities.

Legalization would not just help balance the scales. It would also help balance the budget. The state, which is facing a $19 billion shortfall—crippling its ability to provide adequate funding for education, childcare and other social services—can ill afford to waste so much money on a failed campaign. But it can surely benefit from a regulated cannabis market; experts estimate that the state could capture $1.4 billion a year in taxes and fees.

To put it plainly, a vote for Prop 19 is a vote for a more sensible drug policy. Establishing a market for pot would free up resources to fund treatment programs for addicts and would allow cops and prosecutors to redirect their focus to more serious criminals—while dealing a sharp blow to the Mexican cartels, which depend heavily on illicit trade in California.

As the election nears, some unusual coalitions are competing to get out the vote. Top candidates from both parties are aligned with moral scolds, prominent law enforcement associations and groups (notably, beer distributors) that have a financial stake in keeping pot illegal. They warn that Prop 19 will unleash a flurry of lawsuits, put the workforce in a permanent and dangerous haze and give kids a free pass to toke up. But recent polls give a slight advantage to the other side: a loose alliance of libertarians and progressives, civil rights advocates, other law enforcement groups, unions and young activists.

Californians have proven the fearmongers wrong before: the legislature decriminalized cannabis in 1975, and voters allowed it for medical use in 1996. If it seems like the whole nation is watching to see if they will do so again this fall, that’s because Prop 19 can set a national example for how to wind down the drug war. And we all have a stake in that.