With five states set to vote on recreational marijuana legalization today, you might find yourself struggling to keep on top of what's at stake. 

Here's what you need to know about Proposition 64, the "California Marijuana Legalization Initiative."

The Basics

Proposition 64 is more comprehensive than any other marijuana ballot measure being voted on this year. It covers details ranging from measures to keep big business from gobbling up the industry, to protecting appellations so that only marijuana grown in the state's famous emerald triangle can use branding associated with the region. But as a result, it's impossible to summarize every detail of this intricate proposal.

Here are some highlights.

Prop 64 would make it legal for people 21 or older to buy and possess up to one ounce of marijuana, excluding concentrates like hash (the cap on those is 8 grams). Customers would pay a 15 percent sales tax on recreational cannabis, which is roughly the same rate as other current and prospective legal states like Arizona and Nevada.

Residents would also be allowed to grow up to six plants per household but not per person. So if a house has four adult occupants, the limit would still be six plants.

Regulation would be overseen by the new Bureau of Marijuana Control, which would be part of the state's Department of Consumer Affairs. The DCA would also handle licensing retailers, distributors and micro-businesses (e.g. craft cannabis growers). The Department of Food and Agriculture would be responsible for licensing cultivators and ensuring the industry is environmentally sound. Meanwhile, the Department of Public Health would license manufacturers of cannabis-based products and product testers. And the state's Board of Equalization would collect cannabis taxes.

So already, Prop 64 is more bureaucratic than other initiatives. But it also has a lot of features geared toward consumer experience, public safety and social justice. Consuming cannabis in public would remain illegal, but Prop 64 would legalize cannabis social clubs (think marijuana bars) so that people can have a puff outside the house. The initiative also includes robust regulations on packaging, labelling and marketing to keep cannabis away from kids. 

The initiative would also overhaul the justice system. Anyone convicted of an offence that would no longer be illegal under the new law would be re-sentenced or released. Arrest and conviction records would be destroyed, giving many victims of prohibition a fresh start. These criminal justice reforms are unique to Prop 64, but they could become commonplace in the future as legal states like Colorado and Washington are still debating how to deal with people who have cannabis convictions.

The proponents

Proposition 64 is backed by former Facebook President Sean Parker, who was played by Justin Timberlake in The Social Network. The initiative also has more official endorsements than any other initiative this year. Some notable proponents from the political sphere include California's Lieutenant Governor Gavin Newsom, several congresspeople, state legislators and political organizations such as the California Democratic Party and the MLK Legacy Democrats.

When the initiative was filed by Newsom earlier this year, the lieutenant governor spoke at a press conference about the diversity of Prop 64's supporters.

"Today, the largest coalition ever formed to support marijuana reform has filed the signatures to qualify the most thoughtful marijuana policy in the nation – with the strictest child protections and billions in new revenue for important programs such as public safety," said Newsom.

It's impossible to mention one of the initiative's supporters without slighting another, so check out the full list to see the various organizations representing law enforcers, religious groups, healthcare professionals and educators who want to repeal prohibition in California. Another prominent support base includes groups that represent racial minorities. These organizations argue that legalization is a civil rights issue.

"Reforming our marijuana laws is an important civil rights issue," according to Alive Huffman - President of the California NAACP. "The current system is counterproductive, financially wasteful and racially biased - and the people of California want it to be fixed.  This measure will ensure that California is not unjustly criminalizing responsible adults while ensuring that our children and our communities are protected and vital state and local services are funded."

The opponents

California's legalization initiative also has way more opponents than we can list in one post. Many of them come from the same base as the campaign's supporters: federal, state and municipal lawmakers, law enforcement groups, healthcare professionals, educators and many others have officially endorsed the anti-Prop 64 campaign.

Even newspapers are split on the issue. While the Los Angeles Times and San Francisco Chronicle have backed the initiative, the Sacramento Bee and Bakersfield Californian oppose Prop 64. But the biggest opposition arguably comes from outside state borders, and we'll address that below.

However, one thing separates the two groups is financing. Ballotpedia reports that as of September 16, the pro Prop 64 campaign has raised over $18 million while the opposition has only mustered just over $700,000. So the no campaign will have a distinct disadvantage when trying to get its message out to voters, who seem very favorable to legalization based on recent polls.

The Bigger Picture

Legalization advocates and prohibitionists will clash in every state with a marijuana ballot initiative this fall. But the Golden State is arguably the biggest battleground between activists on both sides of the cannabis issue because what happens in California will have repercussions for the legalization movement in America. 

"California tends to be not just a cultural trend setter in this country but also a political trend setter," Paul Armentano - Deputy Director of NORML - told Civilized. "So it's certainly plausible that a significant win in California will have ripple effects across the United States."

That sentiment is shared by Kevin Sabet, who heads the anti-cannabis group Smart Approaches to Marijuana (SAM). "If there's one thing we agree on with legalization advocates, it's that California is important," Sabet told The Los Angeles Times last August. 

And some think that the legalization movement will be hobbled if California and a few other states fail to repeal prohibition this fail. 

“If we don’t win California and at least half of the other states in play right now, the public narrative around our industry will dramatically change for the worse and for quite some time, setting us back a decade or more,” Aaron Smith - Executive Director of the National Cannabis Industry Association (NCIA) - said at a convention in Oakland last June.

5 States are voting on recreational use of cannabis in 2016. Arizona, California, Maine, Massachusetts, and Nevada.