During a series of YouTube interviews Thursday, President Obama demonstrated a remarkably laissez-faire attitude toward marijuana legalization experiments in the states. And he signaled strongly that the Obama administration wouldn't be taking to the hustings to try to beat back legalization efforts, as previous administrations had been wont to do.

"What you're seeing now is Colorado, Washington through state referenda, they're experimenting with legal marijuana," the president said in response to a question from YouTube host Hank Green. "The position of my administration has been that we still have federal laws that classify marijuana as an illegal substance, but we're not going to spend a lot of resources trying to turn back decisions that have been made at the state level on this issue. My suspicion is that you're gonna see other states start looking at this."

Indeed. Legalization bills are already popping up in state legislatures around the country, and while it's unlikely—though not impossible—that any of them will pass this year, 2016 looks to be the break-out year for freeing the weed. One state is going to be the first to legalize it through the legislature, and next year seems reasonable. And the presidential election year is also likely to see successful legalization initiatives in several more.

Currently four states—Alaska, Colorado, Oregon, and Washington—and the District of Columbia have ended pot prohibition. But that's only about 18 million people. By the time they quit counting the votes on Election Day 2016, that number is likely to triple, and then some.

So, where's it going to happen? Here's where:

California

That California is the only state on the West Coast to not yet have legalized pot is an embarrassment to Golden State activists. They were first with medical marijuana in 1996, and they tried to be first to legalize it with Prop 19 in 2010, but came up short, garnering 46% of the vote on Election Day despite leading in the polls up until the final weeks. In 2012, with the big players sitting on their cash stashes, none of the competing initiative efforts even managed to make the ballot.

It will be different in 2016. The actors with deep pockets are all ready to get involved next year, the polling is good (if not great, hovering in the mid-50s), and the state's disparate and fractious cannabis community is already working to forge a unified front behind a community-vetted initiative. The main vehicle for activists is the California Coalition for Cannabis Law Reform, which has already started holding meetings statewide to try to a unified marijuana reform community.

With 38 million people, California is the big prize. It's also an expensive place to run an initiative, with the cost of getting on the ballot alone at around a million dollars. And it'll take several million more to pay for advertising in the key final weeks of the campaign. But the money is lining up, it'll take fewer signatures to qualify for the ballot (thanks to the dismal turnout in last year's mid-terms), and once it qualifies, it will have momentum from (by then) four years of legalization in Colorado and Washington and two years of it in Alaska and Oregon. California will go green in 2016.

Nevada

Nevada is the state that is actually furthest down the path towards legalizing it next year. The Marijuana Policy Project-backed Coalition to Regulate Marijuana Like Alcohol in Nevada has already qualified a legalization initiative for the 2016 ballot. It would legalize the possession of up to an ounce by adults 21 and over and allow for taxed and regulated marijuana commerce.

Under Nevada law, the legislature now has a chance to approve the initiative. If it does so, it would become law; if it rejects it or fails to act on it, it then goes to the voters on Election Day 2016.

Nevadans approved medical marijuana in 1998 (59%) and again in 2000 (65%), but voted down decriminalization in 2002 (39%) and legalization in 2006 (44%). But it has since then effectively decriminalized possession of less than ounce, and it's now been a decade since that last legalization initiative loss at the polls. Either marijuana will be legal by Election Day 2016 thanks to the legislature or the voters will decide the question themselves at the polls.

Arizona

In Arizona, possession of any amount of pot is still a felony, but polling in the last couple of years shows support for legalization either hovering around 50% or above it. Those aren't the most encouraging polling numbers—the convention wisdom is that initiatives want to start out at 60% support or better—but a serious effort is underway there to put the issue before the voters in 2016.

The Marijuana Policy Project (MPP) is teaming with Safer Arizona and other state activist groups for the 2016 initiative campaign and has formed a ballot committee to begin laying the groundwork for a Colorado-style initiative.

The initiative language is not a done deal, and there are some signs that local activists aren't completely happy with MPP's proposed language, but that's why there are consultations going on.

Maine

The Marijuana Policy Project has been laying the groundwork for a statewide legalization initiative in 2016 with local initiative campaigns in some of the state's largest cities in 2014 and 2013 and is working on final initiative language now. But it is also seeing competition from a state-based group, Legalize Maine, that says it is crafting its own initiative and is criticizing both MPP and Maine politicians for advancing "out of state corporate interests" at the expense of Mainers.

Whether MPP and Legalize Maine can get together behind a single initiative remains to be seen. If they can, good; if they can't, well, Maine is a small and relatively inexpensive state in which to run a signature-gathering campaign. There could be not one, but two legalization initiatives in Maine next year.

Meanwhile, state Rep. Diane Russell has filed a legalization bill in the legislature this year. Maine is one of the states where the looming presence of legalization initiatives could actually move the legislature to act preemptively to craft a legalization scheme to its own liking.

Massachusetts

Massachusetts is another. As in Maine, but to a much greater degree, Bay State activists have been laying the groundwork for legalization for years. Groups such as MassCann/NORML and the Drug Policy Forum of Massachusetts have run a series of marijuana reform "public policy questions" in various state electoral districts each election cycle since 2000—and they have never lost! The questions are non-binding, but they're a clear indicator to state legislators where voter sentiment lies.

The state has also seen successful decriminalization and medical marijuana initiatives, in 2008 and 2012, respectively. In both cases, the initiatives were approved with 63% of the vote. And again as in Maine, the Marijuana Policy Project is organizing an initiative, but local activists with similar complaints to those in Maine are threatening to run their own initiative. Organized as Bay State Repeal, which includes some veteran Massachusetts activists, the group says it wants the least restrictive legalization law possible. Whether the two efforts can reach a common understanding remains to be seen.

Meanwhile, the issue could move in the legislature in the next two years. New Republican Gov. Charlie Baker says he's opposed to legalization, but is praising Democratic Senate President Stanley Rosenberg's decision to appoint a special Senate committee to examine issues around legalization. Rep. David Rogers (D-Cambridge) isn't waiting. He's filed a legalization bill, and while previous such bills have languished in the Joint Committee on the Judiciary, incoming committee head Sen. Will Brownberger (D-Boston) has said he will give it a hearing. Something could happen this year, although it's more likely next year, and the voters doing it themselves on Election Day 2016 is more likely yet.

Vermont

Vermont could be the best bet for a state to legalize it this year and for the first state to legalize it through the legislative process. There is no initiative process in the state, so that's the only way it's going to happen. And the state has already proceeded well down that path.

Gov. Peter Shumlin (D) has endorsed legalization in principle—the devil is the details—and the legislature last year approved a RAND study on the impacts of legalization, which was just released earlier this month. That study estimated that freeing the weed could bring the state $20 to $70 million in annual pot tax revenues.

Other state officials have expressed openness to the idea, and a May 2014 poll found 57% support for legalization. There's not a bill in the hopper yet this year, but one could move quickly in this state where a lot of the legislative groundwork has already been laid.

The Marijuana Policy Project has formed the Vermont Coalition to Regulate Marijuana to help push the process along. Stay tuned; this is one to watch.

Missouri

And there's a dark horse in the heartland. The Missouri activist group Show Me Cannabis has been running an impressive educational campaign about marijuana legalization for the past few years. The group tried to get an initiative on the ballot last year, but came up short.

They've already filed paperwork for 2016 for a constitutional amendment to make it legal to grow, sell, and use marijuana for people 21 and over.

One reason Show Me Cannabis came up short in 2014 was the lack of support from major players outside the state. Given the lack of polls showing strong support for legalization, the big players remain sitting on their wallets, but that could change if good poll numbers emerge. And there's still plenty of time to make the 2016 ballot.