In just a few years, marijuana legalization advocates have gone from being part of a long-shot movement to representative of a view held by 58 percent of Americans.
The quick trajectory of this type of social movement is far from exclusive to legal pot. In recent years, the same-sex marriage movement in particular has been characterized by a rapid change in public opinion and multiple court decisions in favor of marriage equality.
But unlike same-sex marriage, marijuana legalization doesn't have much establishment support. Politicians and lawmakers have remained as far away from the issue as possible even as retail sales for marijuana began in Colorado and Washington earlier in the year. The only major Supreme Court decision on the issue (Gonzales v. Raich) allowed the federal government to continue enforcing prohibition in California even after the state's voters legalized medical marijuana.
The political caution and lack of judicial intervention might explain why marijuana legalization hasn't progressed as swiftly as public opinion. But there are some indications that could change — if the movement overcomes some key hurdles.
Legalization has relied on popular support in a few states, but that could change
Fabio Rojas, a professor at Indiana University who studies social movements, said that these movements tend to be driven by ballot initiatives, lobbying of policymakers, or mass protests that raise awareness.
Up to this point, the marijuana legalization movement has largely relied on ballot initiatives to change state laws. Colorado and Washington voters legalized marijuana at the polls in 2012, and legalization measures are on the ballot in Alaska, Oregon, and Washington, DC, in November.
It's possible politicians will eventually pick up the issue with more force. Once same-sex marriage reached majority support and became law in several states, some politicians, including President Barack Obama, began talking about their "evolutions" on the issue and eventually came out in support of marriage equality.
With rising public support and legalization in a couple states, marijuana legalization appears to be following a similar trend. The Obama administration is openly allowing legalization efforts to continue in Colorado and Washington with minimal federal interference. Outgoing Attorney General Eric Holder, who heads the Department of Justice, said the federal government should take another look at marijuana's restrictive legal classification. Hillary Clinton, too, said that she's open to letting the states act as "the laboratories of democracy" for full legalization efforts — perhaps in preparation for a likely presidential bid in 2016.
As a result, legalization advocates expect to rely less on ballot initiatives over time. The Marijuana Policy Project (MPP) plans to lobby several state legislatures, particularly in New England and Hawaii, to legalize marijuana by 2017. This kind of approach has worked for MPP before: Several states first legalized medical marijuana through ballot initiatives in the late 1990s and early 2000s, but in recent years more state legislatures — most notably, New York — have allowed the drug for medicinal purposes.
"Up until the past year or so, the work has been primarily focused on medical marijuana and decriminalization," said Mason Tvert, spokesperson of MPP. "At this point, there are a number of states that look like they will be adopting laws regulating marijuana like alcohol through their legislatures in the next few years."
Rojas of Indiana University suggested the advancements of the movement could be a self-perpetuating cycle: As more states legalized medical marijuana, Americans saw that the risks of allowing medicinal use didn't come to fruition as opponents warned. That reinforced support for medical marijuana, which then made politicians more comfortable with their own support for reform.
A similar cycle could be playing out with full legalization, Rojas explained. As voters see medical marijuana and legalization can happen without major hitches, they might be more likely to start supporting full legalization.
"People said, 'Okay, now that someone else is throwing this out in public, it's okay for me to vote for it or approve it,'" Rojas said. "That's probably the main driving force: using the electoral system to push ideas that people may be afraid to think about or consider because they're illegitimate — or at least they were."
The rapid change in public opinion could have been helped along by the internet, which allows people to share stories about their own pot use, research about the issue, and states' experiences with relaxed marijuana laws much more quickly.
"When I was a college student around 1990, other than hardcore political wonky types, … nobody really talk about drug legalization," Rojas said. "Now, you can go on Facebook or Twitter or Instagram, and people can share a news story. You get exposed to it constantly."
The legalization movement still faces major hurdles
When talking to advocates of legal pot, they often point to the trend in public opinion and strong support among millennials as evidence that legalization is practically inevitable.
"If a law doesn't pass this year in a particular state, then it will likely pass within the next couple years in that state," Tvert said. "People are coming to realize this is not what they once thought it was."
Supporters often compare their expected trajectory to what happened with same-sex marriage politics: In just a few years, the movement will change from an uphill struggle to crossing a tipping point from which the country perhaps can't and doesn't want to turn back.
But the legalization movement still faces a lot of resistance from lawmakers, even after Gallup found 58 percent support for legalization in 2013.
Rojas of Indiana University indicated the lack of support from lawmakers reflects the strong establishment support — and financial incentives — behind marijuana prohibition. Police departments, for instance, get millions in federal funding to fight the war on drugs. If marijuana was legal, some of that money for police departments could dry up.
"In the case of gay rights, people have a prejudice against gays, but there are very few people who draw a paycheck out of it," Rojas said. "When it comes to drugs, lots of people are drawing paychecks from it."
Unlike other social movements, marijuana legalization also doesn't have a civil rights claim built into it. With same-sex marriage, a gay or lesbian couple can intuitively argue that they should be able to use their fundamental right to marry who they want to receive equal benefits under the law. The civil rights issues surrounding marijuana, such as the disproportionate enforcement of the law on black communities, are more nuanced and less intuitively linked to legalization.
"When it comes to [marriage] rights, it's the freedom to do the right thing," Rojas said. "When you're talking about a personal vice like drinking alcohol or smoking drugs, that's the freedom to do wrong."
Daniel Schlozman, a political scientist at Johns Hopkins University, argued there hasn't been a strong incentive for politicians and lawmakers to take charge on the issue. Despite majority support, legalization isn't a hugely important issue for most Americans. When asked about their priorities, voters typically cite the economy, education, health care, and national security. Social policy movements, even LGBT rights, tend to fall much lower on the list.
The legalization movement also doesn't have the kind of established support and fundraising potential that often woos political candidates. Both have existed within the LGBT rights movement for years: In the three days after President Obama announced his support for same-sex marriage, Obama's re-election campaign saw a roughly $6 million bump in fundraising.
Politicians generally need a concerted movement "that will give [them] time and money and networks [they] can't get otherwise," Schlozman said. "Without that kind of preference intensity, if you're [Senator] Bernie Sanders, you're going to want to talk about social democracy, and if you're [Senator] Elizabeth Warren, you're going to want to talk about the banks. There's no particular reason for you to dilute your core efforts to move the party."
Politicians may be cautious in part because public opinion still has time to change. It's possible — although not the case so far — that legalization could end up going horribly wrong in Colorado, Washington, and other states that approve it. The public could turn against legalization if drug abuse skyrockets or if the marijuana industry tries to take advantage of drug abusers for profit.
Schlozman pointed to the Equal Rights Amendment, which attempted to establish equal rights for women in the US Constitution, as a movement that at one point seemed headed for victory but quickly fizzled. Toward the end of the ERA's approval process in the late 1970s, opponents mounted a strong campaign, playing up anti-war fervor by pointing out the amendment would let women get drafted into the military. That led to a drop in support from the public and lawmakers. "Public opinion is fickle," Schlozman said.
Combined, all these factors make it possible, even likely, marijuana legalization could see a slower course than an issue like same-sex marriage. Over time, the question is whether and when Americans' support for legalization will become prominent enough to prevail over an established opposition and a sense of apathy, even among supporters, toward the issue.
To learn more about marijuana legalization, check out Vox's full explainer and previous interview with Mark Kleiman, one of the nation's leading drug policy experts: