In 1996 the therapeutic uses of marijuana in easing the symptoms of serious illnesses like HIV, cancer, epilepsy, PTSD, and glaucoma. Recently, marijuana’s potential value for treating chronic pain has garnered attention as an alternative to opioids. Nationally, support for marijuana has never been stronger. Seventy-two percent of Democrats and a narrow majority of Republicans support legalization, according to Gallup.  Strong public support and successive waves of state-level legalization in election years have led many policy analysts to argue that marijuana has reached a tipping point in the United States. Two-thirds of all US states have now legalized some kind of marijuana. After that, the argument goes, its nationwide expansion is inevitable. As marijuana policy researchers, we question that narrative. Our research indicates that medical marijuana progress may well stall after this latest round of successful ballot initiatives. Recreational marijuana may continue to expand into states with legal medical marijuana but will ultimately hit a wall, too. Our caution has to do with the particular way marijuana legalization has occurred in the United States: at the ballot box. Rather than relying on lawmakers to write and pass legislation on certain issues often, controversial ones — ballot initiatives harness public opinion. They have been used to legalize or restrict same-sex marriage, place limitations on taxing and spending, raise the minimum wage, and much more. Some are funded by wealthy individuals with specific business interests. The Marijuana Policy Project, an advocacy organization, said it would put medical marijuana on another states ballot in 2016. In response, Legislature moved quickly to craft and pass its own medical marijuana legislation.  History shows that once people grow comfortable with medical marijuana — seeing its impacts on patients and tax revenues — full legalization often follows. In our analysis, the remaining 13 states are very unlikely to liberalize access to marijuana without a significant push by the federal government says marijuana doctors in Florida. That’s unlikely, but not impossible, under the Trump administration. Federal law still considers marijuana an illegal Schedule I drug under the Controlled Substances Act, meaning that as far as the US government is concerned, the plant has no medical value.