Washington State voters legalized marijuana last night. It was not just a gesture. It was not simply a statement.

Short version: You can legally possess up to an ounce of pot starting on December 6, and the city's prosecutor says there's nothing the feds can do about it.

Full version: By passing Initiative 502, we triggered a complex process to, for the first time in US history, create an above-board marijuana market, but put that out of your head for just a second. All that stuff will be hashed out in the next few years. (The regulations could potentially create a conflict with federal law—many say it doesn't create a conflict with federal law, and others say it does—but that has no bearing on the most important aspect of this law.) Here's what you need to know now. Starting on December 6, I-502's "Section 20" takes unequivocal effect:

The possession, by a person twenty-one years of age or older, of useable marijuana or marijuana-infused products in amounts that do not exceed those set forth in section 15(3) of this act is not a violation of this section, this chapter, or any other provision of Washington state law.

What this means is that in one month, adults 21 and older can legally possess up to one ounce of bud, 16 ounces of solid-form marijuana food products, and 72 ounces of cannabis in liquid form (such as lotions or, like, a shocking volume of hash oil). You can also have pot paraphernalia.

This portion of the law, says Seattle City Attorney Pete Holmes, who is both a prosecutor and a co-sponsor of the initiative, "is simply not preemptable." In other words, Holmes is saying that feds may challenge the licensing and the stores—but not the possession portion. Furthermore, "The feds cannot make the state criminalize that kind of conduct," he says.

So here's what it means for you: You can have that pot on you legally. You can have it in your home legally. There is no probable cause to arrest someone for possessing marijuana. Provided that you're not using it in public (just like you can't drink in public, which is a dumb rule, but it's parity), it's legal. Using it in public becomes an infraction, just like drinking whiskey on the sidewalk. You also can't drive high. These parts of the law can't be challenged by the feds, Holmes insists. Even though possession technically remains a federal crime, the feds as practical matter don't arrest or prosecute people for small-time possession, unless people do it on federal property. It basically doesn't happen.

So what happens to existing pot cases?

Ian Goodhew, deputy chief of staff for the King County Prosecuting Attorney, says his office is trying to figure out whether they will charge pending marijuana possession cases. "We haven't figured out how we will handle all of those cases," he says. But assuming the possession portion of the law is not federally challenged—and no credible lawyer thinks the possession portion can be—Gooodhew says that in future cases, "we cannot charge someone under state statue."

In summary: Pot possession becomes legal in one month in Washington, there will be no state law to prosecute people for possession, the feds can't challenge that part of the law, and the state can't charge under federal law.

That part's a done deal.