As midterm mania reaches a fever pitch, and hundreds of millions of dollars are spent to influence which party will control the house and senate after 2 November, another important neck-and-neck race in the bankrupt and beleaguered state of California is causing a lot of… buzz. This November, the electorate of California, the nation's most populous state, will vote on Proposition 19, a measure to decriminalise marijuana, the most recent manifestation of nation's confused regulatory relationship with the devil weed. Over a dozen US states have already decriminalised possession or personal use of cannabis, and Denver, Colorado and Oakland, California are already home to thriving (and profitable) medical marijuana industries.

Meanwhile, in liberal New York City, we've seen a sweeping expansion of marijuana-related arrests in the last few years, and in LA and other major cities of California, black people are arrested at twice, thrice and up to seven times the rate of white people, despite federal studies that show that marijuana is used more commonly by white Americans, according to the Drug Policy Alliance.

All the while, an expanding body of academic and medical evidence is increasingly telling us what medical marijuana advocates, and stoners, have been screaming all along – pot is actually pretty good for you, the individual, and for us as a society. From a variety of salutary health effects, to its ability to pump and prime an economy in tatters (California again), cannabis sativa never looked so good – and pot advocates have the data to prove it. Californians, please take note…

Marijuana may halt or slow cancer

According to peer reviewed studies in the Journal of the National Cancer Institute, Cancer Journal, and most recently, Molecular Cancer, cannabinoids, the generic term for compounds found in cannabis, possess strong anticancer properties that slow or stop the growth of cancer in a wide range of cancers. Researchers in Spain write that cannabinoids "might constitute a new therapeutic tool for the treatment" of cancerous tumors.

Marijuana can help with your memory loss (if you suffer from Alzheimer's)

Researchers at Ohio State University and a team of scientists from Israel and Spain found that cannabis can help slow memory loss amongst those with Alzheimer's. Not only that, another study published in 2008 in the journal Neurobiology of Aging found that THC, the primary psychotropic ingredient in marijuana, might help prevent the onset of Alzheimer's.

Marijuana can help solve the States' budget crisis

With state budgets still reeling during the Great Recession, and layoffs of public employees widespread, Colorado's recent solution might give other states pot envy. The Rocky Mountain state is using funds from its medical marijuana programme cash fund to help close this year's $60m budget shortfall. Take note California. The fiscal basketcase of a state, where marijuana is the biggest cash crop, could collect $1.4bn in new tax revenues – if Proposition 19 is approved, this fall.

The (pot smoking) kids are all right

Researchers at the University of Lausanne, Switzerland, in a recent study published in the prestigious Archives of Pediatrics and Adolescent Medicine journal, found that compared with teetotalers, kids who smoke pot "are more socially driven… are significantly more likely to practise sports, and they have a better relationship with their peers."

Legal pot in the US could drastically reduce the bloodshed in Mexico

While the Mexican parliament decriminalised pot for personal use in 2006, the massively lucrative illicit market in the US has bolstered the fortunes of the dizzying array of Mexican cartels and regional mafias responsible for almost 30,000 murders in the last few years. According to the White House office of national drug control policy, over 60% of the cartels' earnings come from marijuana sales in the US, some of which is now being grown on vast swathes of public land north of the border, enabling the cartels to avoid border interdiction efforts altogether.

Former Mexican foreign minister Jorge G Castañeda, in a recent op-ed in the Washington Post, had this to say of a post Prop 19 future:

"Legalisation would make a significant chunk of that business vanish. As their immense profits shrank, the drug kingpins would be deprived of the almost unlimited money they now use to fund recruitment, arms purchases and bribes… Before Mexico's current war on drugs started, in late 2006, the country's crime rate was low and dropping. Freed from the demands of the war on drugs, Mexico could return its energies to again reducing violent crime."

Marijuana makes you feel good (especially if you're sick)

A 10-year study by the Medicinal Cannabis Research Centre at UC San Diego found that cannabis is a great palliative for a nerve damage condition called "painful peripheral neuropathy", which up to 10% of people in the US suffer from. Pot also helped patients with multiple sclerosis by reducing or preventing the frequent muscle spasms associated with the disease. And a study published in the journal Neurology found that, unequivocally among HIV patients, smoking pot, "effectively relieved chronic neuropathic pain from HIV-associated sensory neuropathy".

Shrinks like it

The American Psychiatric Association, the largest association of psychologists worldwide, has voted unanimously in support of medical marijuana. "Seriously ill patients living in these states with medical marijuana recommendations from their doctors should not be subjected to the threat of punitive federal prosecution for merely attempting to alleviate the chronic pain, side effects, or symptoms associated with their conditions or resulting from their overall treatment regimens," reads the APA action paper in support of the motion.

Marijuana could make us rich. It already is (but the tax man isn't getting a cut)

According to the most recent numbers, marijuana is by far the biggest cash crop in the United States, outpacing corn, soy, hay, vegetables, wheat, cotton, rice and any other number of commodities. Unlike other commodities, though, sales are tax-free, and because the product is illegal, the kind of Mad Men (and Women) who specialise in pot marketing, product positioning and PR are missing out on the chance to come up with the latest jingle or ad campaign for the next bumper crop. And despite (or because of) the horror show economy, demand is high. One estimate, by a conservative thinktank, puts untaxed consumer spending on marijuana in the US at between $45bn and $110bn a year. Imagine what the doper's Don Draper could do with that account.

• This article was amended at 17:33 GMT on 26 October 2010. The original version referred to a "schizophrenic regulatory relationship with the devil weed". It is Guardian policy to use the term "schizophrenic" only in a medical context.