Weed is legal in at least some form in 22 states and the District of Columbia. Most allow it for medical use only. Colorado and Washington this year enacted laws that allow recreational use by adults.
But more than two dozen states are considering new or expanded marijuana reform legislation, including complete legalization for adults, medical marijuana, hemp use and decriminalization.
"A lot of legislators are more open, they’re holding more hearings, they’re emboldened."
Minnesota a week ago passed a medical marijuana law, and 14 other states have reform bills or ballot initiatives on the table: Arizona, Hawaii, Maryland, Massachusetts, Missouri, New Hampshire, New Jersey, New York, Oklahoma, Oregon, Pennsylvania, Rhode Island, Vermont, and Wisconsin.
Meanwhile, 12 states and the District of Columbia are considering decriminalization: Alabama, Arizona, Hawaii, Illinois, Louisiana, Michigan, Missouri, New Hampshire, New York, North Carolina, South Carolina and Wyoming.
And 11 states are considering legislation to establish effective medical marijuana programs: Florida, Kansas, Kentucky, Hawaii, Michigan, New York, Pennsylvania, Tennessee, West Virginia, and Wisconsin.
Three states are even considering allowing industrial hemp cultivation: Indiana, New York and Tennessee.
While medical marijuana is becoming an easier fight to win, advocates for full legalization — including recreational use — see the most hope for further victories in Alaska, where a vote is scheduled for November. California and Oregon may also provide favorable battlegrounds next year.
All three states have already decriminalized pot and have approved medical marijuana.
"It’s definitely a clear shift in public attitude on this issue," said Mason Tvert, communications director for the Marijuana Policy Project, a group spearheading the coordination of state efforts. "A lot of legislators are more open, they’re holding more hearings, they’re emboldened."
A poll conducted earlier this year by the Pew Research Center found that 75 percent of respondents — including majorities of both supporters and opponents of legal marijuana — think that the sale and use of cannabis will eventually be legal nationwide.
Other recent surveys have found that, while Americans are fairly split on whether weed should be fully legalized like alcohol and cigarettes, about 85 percent are in favor of allowing doctors to prescribe it.
Kevin Oliver, executive director of the Washington state chapter of the National Organization for the Reform of Marijuana Laws, believes that California, where voters approved the first medical marijuana laws in 1996, will be a harbinger again, with a push for a vote on legalization this November or in 2016.
The biggest argument for the reefer gladness could be money: Colorado is projected to rake in more than 40 million in tax revenue from legalized marijuana this year.
But Kevin Sabet, who co-founded Smart Approaches to Marijuana and served as a drug policy adviser to Presidents George W. Bush and Barack Obama, said the push to make weed legal is a "slippery slope."
"We don't smoke opium to get the effects of morphine, nor do we need to smoke marijuana to get its potential medical benefits," Sabet, the director of the Drug Policy Institute at the University of Florida, told NBC News.
"We need medications, based on marijuana, at pharmacies and available through legitimate doctors — the current setup in California and Colorado has turned into nothing less than de facto legalization for anyone with a headache."
Here's a look at the next five states likely to legalize marijuana:
Alaska: Ballot Measure 2, which is set to be voted on in the Nov. 4, 2014, election, is one of the best chances advocates have of pushing full legalization to a third state. If approved by voters, the measure would allow adults 21 and older to possess up to an ounce of marijuana (28 grams), and up to six plants.
California: The California Control, Regulate and Tax Marijuana Initiative was approved for circulation as a potential proposition on the November 2014 ballot, but its sponsors have slowed down efforts with the idea that they will have a better chance at success in 2016 when the presidential elections bring out more liberal voters. The measure, which currently exists in two versions, would legalize “limited amounts” of marijuana for adults over 21.
Arizona: The Arizona Legalization of Recreation Marijuana Amendment could appear on this year's ballot in November, as a state constitutional amendment, but the effort also could be pushed back to 2016. The measure would change the state constitution to allow citizens 18 years and older to grow, smoke and possess marijuana in amounts up to 2.5 ounces — although the 2016 version set the cut-off at 21 years old.
Maine: One of the few states where legalization has been gathering steam on a city-by-city basis. In 2013, Portland legalized possession for less than 2.5 ounces of marijuana for residents 21 and older. A popular statewide bill failed last year -– an off-cycle year for national elections -- but is expected to be reintroduced in 2014.
Oregon: The Oregon Legalized Marijuana Initiative will appear on the ballot this November — if organizers can collect about 90,000 signatures before a July 3 deadline. Backers have expressed confidence that they will hit that mark. If approved this fall, the recreational use of marijuana would be legal for adults 21 and over.