Joe Biden's bold experiment in trying to win the Democratic presidential nomination without a single vote from a young person continued Saturday, when the 76-year-old frontrunner told a crowd in Las Vegas that he doesn't want to legalize weed because he's worried that it might lead to harder drugs. Here's what the former vice president said, according to Business Insider:

"The truth of the matter is, there's not nearly been enough evidence that has been acquired as to whether or not it is a gateway drug," Biden said. "It's a debate, and I want a lot more before I legalize it nationally. I want to make sure we know a lot more about the science behind it."

If you heard something just now, that was the sound of thousands of cannabis experts sighing all at once. The "gateway drug" debate never seems to die, even though there is ample evidence that smoking weed does not lead users down a pathway to heroin or meth addiction. Writer and harm-reduction expert Maia Szalavitz did a thorough dismantling of the gateway myth for VICE in 2015. Though it is true that people addicted to these more harmful drugs often start out with weed, it's not the that cannabis somehow activates a tendency toward addiction inside these people. As Szalavitz lays out, addiction is a complex phenomenon that can be triggered by some combination of genetic predisposition, mental illness, childhood trauma, and other factors. People who seek out drugs as a way to self-medicate may start out with weed, but that does not mean that most, or even many, people who smoke pot are going to try other drugs, much less become addicted to them.

"If marijuana were causing other drug use, most users should progress to more dangerous substances," Szalavitz wrote. "But they don't. By the numbers, marijuana use seems more like a filter that keeps most people out than a gateway that lets the majority pass through."

Opponents of legalization like Biden may point to a recent study showing that as more states have legalized cannabis, the U.S. has seen an uptick in people with cannabis use disorder, which went from 0.9 to 1.23 percent from 2008 to 2016. But the author of that study doesn't see those results as being an argument against legalization. Even if the government has to contend with some negative public health effects as a result of legal cannabis, the tradeoff of increased tax revenue and helping roll back some of the effects of the racist war on drugs is undoubtedly worth it.

Most Americans agree with these pro-legalization arguments—or maybe they just instinctively agree that getting arrested for weed is dumb. The most recent Pew poll on the subject found that a record two-thirds of Americans (and 78 percent of those who lean Democrat) support legalization, and the vast majority of Democratic presidential candidates (basically everyone except Biden) supports legalization.

It is true that Biden wants to decriminalize cannabis on a federal level, and is in favor of allowing states to legalize. But his plan to reclassify weed as a Schedule II drug has cannabis businesses freaking out, as that move would put it under control of the Food and Drug Administration, which might strictly regulate it as a medication, raising the possibility that the recreational cannabis market as it exists in many states might be wiped out. And it's unclear whether Biden would do anything about the problems faced by weed-based merchants that are locked out from the banking system as a result of its illegal federal status. (VICE contacted the Biden campaign to ask whether he'd support a law to fix this, a la the SAFE Banking Act, which Democrats recently passed out of the House, but did not receive a reply.)

Biden's continued belief in the gateway drug myth might be explained by his age, as many older Americans still don't support legalization. But let’s avoid ageism and just call him out of touch. Cannabis legalization is widely popular, especially among Democrats, and the current debate has centered around how to legalize the drug in order to minimize public health problems and to make sure that the communities that were harmed by the war on drugs benefit from its end. That Biden isn't participating in those conversations, and is instead talking 90s-esque bullshit about how weed is dangerous, is a slap in the face to everyone who cares about the issue. On weed, Biden isn't just cautious, he's fully out of the mainstream.

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