For years, the only place scientists have been able to get cannabis is the University of Mississippi, and a single producer doesn’t have much incentive to grow the best quality cannabis they can.

Some scientists on the cutting edge of demonstrating cannabis’s medicinal value say they can’t even conduct their research with the product the University of Mississippi provided.

Apparently, it was enough to convince the DEA to say they were going to do something about it—then never did. The reason isn’t a secret. A year after the announcement, the DEA stopped accepting applications under a new Justice

Department head, Jeff Sessions. Even Sen. Orrin Hatch (R-Utah), one of the oldest, most conservative white guys you’re going to find in Congress, pushed Sessions on the topic when he introduced a bill to open up cannabis research.Not to be out-curmudgeoned, Sessions brushed off his questions.

Hatch’s bill, co-introduced with Sen. Brian Schatz (D-Hawaii), would have encouraged research, increased availability and required the National Institute on Drug Abuse to publish best practices for growing cannabis.

Luckily, many patients seem to discover themselves what dosage works for them, and there’s certainly no shortage of experience and knowledge in the industry from growers and scientists.

But in the absence of such a welcoming environment, those trying to legalize cannabis, or advocating new qualifying conditions, are at a loss for data to prove what they anecdotally know.

Take the Mothers Advocating Medical Marijuana for Autism, for example. They’ve petitioned the Arizona Department of Health Services to add autism to the list of the state’s qualifying conditions several times, each time being met with another excuse.

They’ve had to rely on recent research from places like Israel and South America, the first studies of their kind, to demonstrate cannabis’s effectiveness in treating autism.

The DEA tells them “there’s not enough data” or “the term’s too broad.” But these are the exact kind of defenses against expanding cannabis use that can be dispelled with more research.

And that’s what Sessions is afraid of.

The United States has come a long way since the days of absolute prohibition. Only four states hold out on any kind of cannabis legalization: Idaho, South Dakota, Nebraska and Kansas. (Nebraska has decriminalized it, though.)

Since Colorado and Washington legalized recreational cannabis in 2016, seven other states have followed, 28 have begun medical programs (many with low-THC/high-CBD oils only) and six have decriminalized it.

The trend is clear, but some people refuse to see it. While Session’s shenanigans are disappointing, and a seemingly small refusal to approve applications is a tiring setback, the argument isn’t whether to legalize cannabis, it’s when.