It's a movement charging ahead — for now.
Legalizing recreational marijuana is currently a priority in more than a dozen states as polls show overwhelming support and lawmakers see a way to bring in hundreds of millions of dollars in tax revenue. So far, eight states have legalized recreational cannabis.
But in recent weeks, the Trump administration has alarmed some pot supporters by warning states that have legalized recreational marijuana — California, Colorado and Oregon, among them — that federal law enforcement agents could soon come after them.
"I am definitely not a fan of expanded use of marijuana," U.S. Atty. Gen. Jeff Sessions told reporters recently. (Last year, Sessions characterized marijuana as a "very real danger.")
Here's a look at the current state of marijuana in America:
When did marijuana legalization begin?
The movement began more than 20 years ago.
In 1996, Californians overwhelmingly passed Proposition 215, which legalized marijuana for medicinal use. Since then, 27 other states and the District of Columbia have passed laws — a mix of voter-approved ballot measures and legislation — legalizing marijuana for medicinal use.
Scientific research has consistently shown that, for certain conditions, marijuana can be of medical value.
Indeed, a report released in January by the National Academies of Sciences, Engineering and Medicine found that there is conclusive and substantial evidence that cannabis is effective for the treatment of chronic pain in adults, including nausea from chemotherapy and multiple sclerosis-related spasms.
Similar findings have shown up in medical reports over the years.
But wait, isn’t marijuana still illegal at the federal level?
Yes — kind of.
Under federal law, marijuana is viewed as a Schedule I drug — the highest classification, also including heroin and ecstasy.
"States, they can pass the laws they choose. I would just say, it does remain a violation of federal law to distribute marijuana throughout any place in the United States, whether a state legalizes it or not," Sessions told reporters.
But states that have legalized medicinal pot have some leeway.
In 2014, Congress passed a spending bill that included a provision that bars the Justice Department from using funds to go after state medical cannabis programs. The provision remains in place.
What about recreational marijuana?
It's not protected under that provision.
Since 2012, eight states — with Colorado and Washington state leading the way — have legalized the sale and possession of marijuana for anyone over the age of 21. One result is that the states are raking in big bucks.
Last year, Colorado brought in nearly $200 million in tax revenue off sales, while Washington state netted about $256 million.
What is the Trump administration planning to do?
It's unclear. Aside from saying states that legalized recreational pot could be targeted for federal action, the administration did not get into specifics, though it certainly suggested a sterner approach than the Obama administration.
White House Press Secretary Sean Spicer likened marijuana use to the opioid addiction epidemic and said the Justice Department would review how to proceed.
What did Trump the candidate say about legal marijuana?
Trump, who rarely faced questions about cannabis legalization on the campaign trial, made remarks that appear at odds with the recent comments from Sessions and Spicer.
"I think it's up to the states," Trump said in an interview with a Denver television station in August. "I'm a states person. I think it should be up to the states, absolutely."
So recreational legalization began under President Obama. What did he do?
To be blunt, mostly nothing.
Other than a few raids early on, the Obama administration viewed marijuana legalization mostly as a states' rights issue.
In a memo released in August 2013, then-Deputy Atty. Gen. James Cole noted that as long as state legalization efforts didn't undermine a range of federal priorities — such as keeping pot out of the hands of minors and preventing marijuana from being grown on public land — his office would exercise prosecutorial discretion.
In other words, the Justice Department directed law enforcement resources to other drug priorities, such as the growing use of opiate painkillers across the country.
Obama, in an exit interview with Rolling Stone in November, said he was not "somebody who believes that legalization is a panacea."
"But I do believe that treating this as a public-health issue, the same way we do with cigarettes or alcohol, is the much smarter way to deal with it," he said.
Are states that have legalized pot looking for help from the federal government?
Because marijuana is illegal under federal law, banks are prohibited from taking money from dispensaries selling pot, forcing an all-cash business that creates persistent fears of violent crime among employees.
Colorado Gov. John Hickenlooper has called on Congress to pass legislation that halts federal regulators from penalizing financial institutions for serving the marijuana industry.
He has support from members of Congress, such as Rep. Jared Polis (D-Colo.), who in February helped form the bipartisan Congressional Cannabis Caucus. The group aims to craft and pass federal legislation that helps states that have legalized marijuana.
"The results are in," Polis said in a statement last month. "A majority of Americans live in a state that has some form of legal access to cannabis, and the federal prohibition of marijuana has been a complete and utter failure."
Are more states looking to legalize?
Yes — many more.
So far this year, lawmakers in 17 states — Connecticut, Minnesota and Hawaii, to name a few — have introduced more than two dozen measures to legalize recreational pot for adults and tax its sales.
"Our focus is on revenue and bringing in cash to the state as legalization becomes more and more widespread," Mary Washington, a state delegate from Maryland who introduced a bill recently that would tax marijuana like alcohol, told The Times. "Why not get it done now? We're elected to do a job. More and more states are moving in this direction."