The data do show one significant demographic fault line, however: age. Legalization is supported by 63 percent of boomers, 65 percent of Gen Xers, and 76 percent of millennials. But among the silent generation— those older than 74 years — support is just 35 percent.
Partisan differences are heavily mediated by age as well. Among the silent generation, for instance, there is a 32-point gap in support between Democrats (53 percent) and Republicans (21 percent). Among millennials, more than 70 percent support legal marijuana, regardless of party affiliation.
In assessing support for marijuana, surveys have typically posed a simple question: “Do you think the use of marijuana should be made legal, or should NOT be made legal?” For this survey, however, Pew researchers posed a separate question to suss out whether Americans back recreational marijuana, medical marijuana, both or neither.
Fifty-nine percent said it should be legal for both medical and recreational purposes, a 10-point increase since fall 2016. Thirty-two percent said it should be legal for medical use only. Just 8 percent said it should not be legal at all, a steep drop from the 15 percent recorded in 2016.
As with many political issues, the public’s preferences on marijuana are well to the left of where the policy currently stands. The plant remains illegal for all purposes under federal law. Recreational marijuana is legal in 11 states plus D.C., in most cases because of voter-approved ballot initiatives. Most other states have some form of medical marijuana law, although in many cases there are severe restrictions on the conditions for which medical marijuana can be used, or on the types of marijuana that can be used.
According to the National Conference of State Legislatures, just four states — Idaho, South Dakota, Nebraska and Kansas — prohibit marijuana use in all forms.
“As more and more states have moved forward with their own marijuana liberalization policies in recent years, public support has only grown stronger,” Erik Altieri, executive director of the National Organization for the Reform of Marijuana Laws, said in a statement. “At a time when the political divide is larger than ever, the issue of marijuana legalization is one of the few policy issues upon which most Americans agree.”
Legalization foes contend that marijuana use comes with negative health effects. This week, the group Smart Approaches to Marijuana (SAM) highlighted the results of a study in the journal JAMA Psychiatry showing a half-percentage-point increase in rates of problematic cannabis use among teens in states that have legalized recreational use.
“Legalization efforts are sending the message that marijuana use is safe and state sanctioned,” SAM President Kevin Sabet said in a statement. "No amount of marijuana use is safe for young people and more must be done to halt its normalization.”
Most of the Democratic presidential candidates support legalizing recreational use in some form or another. But there are notable outliers, among them former vice president Joe Biden, who long supported “tough on crime” legislation while he was in the U.S. Senate. He opposes legalization but has signaled a preference to reduce criminal penalties for pot use.
Billionaire Democratic hopeful Mike Bloomberg recently called marijuana legalization “the stupidest thing anyone has ever done.”
President Trump, meanwhile, has had little to say about marijuana one way or another during his time in office, though he did recently reiterate support for letting states decide their own policies.