Nearly three years after the Drug Enforcement Agency announced it would end a monopoly on who can grow cannabis for legally sanctioned research, there’s still only one federally authorized cannabis cultivator in the United States.

And the limited supply of research cannabis is hampering the speed, quality and range of studies that scientists can conduct on the potential medical benefits, or harms, of marijuana — even as demand for reliable cannabis research soars.

“It is politics and not science that is interrupting the conduct of this research,” said John Hudak, a fellow at the nonprofit Brookings Institution who specializes in marijuana policy. “And that is not something that Americans should stand for.”

A bipartisan group of 28 members of congress — led by Rep. Eric Swalwell, D-Dublin, and including Southern California Reps. Lou Correa, D-Santa Ana, and Gil Cisneros, D-Yorba Linda — is seeking answers.

They sent a letter this week calling for Attorney General William Barr and Uttam Dhillon, head of the DEA, to remove red tape now blocking cannabis research. And they requested an update regarding the 26 applications to grow marijuana for sanctioned research that have been submitted over the past three years.

None of those applications have been denied or approved, DEA spokeswoman Katherine Pfaff said Tuesday. When asked about the lengthy delays, Pfaff paused and said, “It’s just still in review.”

Correa, who represents central Orange County’s 46th District, said his push for answers stems largely from his work with veterans.

“With the opioid crisis raging across America, it is imperative to the health and safety of our veterans that we find new treatments for chronic pain and service-related injuries,” Correa said via email. “Cannabis is a promising alternative; however, the DEA’s monopoly on cannabis production prevents vital medical research from being conducted and denies our veterans the opportunity to find relief.”

Since 1968, the University of Mississippi has had a monopoly on growing the cannabis used in U.S. studies on how the drug affects people.

The DEA says it’s never turned down a qualified request for cannabis research.

To keep up with growing demand from researchers — now that 10 states have legalized recreational marijuana and 33 have legalized medical cannabis — the agency approved letting the University of Mississippi grow five times more marijuana this year than the year before. And, while eight researchers received marijuana from the Mississippi school in 2015, the National Institute on Drug Abuse reports that the number rose to 20 in 2018.

But scientists have long complained that the cannabis being supplied by Ole Miss is low quality and doesn’t represent the range of products people are consuming today. The university has made efforts in the past couple of years to improve the quality of its supply, but Hudak said it’s still nowhere close to meeting the needs of researchers.

Three years ago, amid mounting pressure, the DEA — then under President Barack Obama — said it wanted to increase the number of cultivators registered to grow marijuana for research. But Hudak believes the Obama administration kicked off those efforts too late to see them through, likely assuming that another Democrat would continue the process after Obama was out of office.

A week after the 2016 election, President Donald Trump appointed Jeff Sessions — a vocal opponent of marijuana legalization — to be Attorney General. And in August 2017, Sessions ordered the DEA to suspend its application program for new cultivators. At the time, more than two dozen researchers had submitted nonrefundable $3,047 fees and supplied lengthy documentation to apply for growers licenses.

“We still haven’t heard anything back on our application and we don’t think anyone else has either,” said Brad Burge, spokesman for the Multidisciplinary Institute for Psychedelic Studies, a Santa Cruz-based nonprofit that applied in February 2017 to grow cannabis for research in partnership with Lyle Craker, a professor of plant and soil sciences from the University of Massachusetts at Amherst.

After almost two years of radio silence, eight U.S. Senators sent a letter giving then-Attorney General Jeff Sessions a deadline of Aug. 10, 2018 for the DEA to address questions about the status of those 26 applications. That deadline came and went.

House representatives sent similar letters in August and September, also with no response.

Burge said his organization was preparing to sue Sessions before the former attorney general resigned, on Nov. 7 of last year.

“So, now it’s up to Barr,” Burge said, adding that the new attorney general has “given indicators that there will be movement, but there hasn’t been any yet.”

Burge referred to an April 10 Senate appropriations hearing, where Sen. Brian Schatz, D-Hawaii, asked the attorney general for an update on the pending applications to grow marijuana for research.

“I have been pushing very hard over the last few weeks to get that process underway, and I think we’re going to move forward on it,” Barr replied. “I think it’s very important to get those additional suppliers.”

“Can you assure me that I’m not going to be here a year later asking the same question?” Schatz asked.

Barr responded: “Yes.”

Based on those comments, Burge believes they may see some action by the administration soon. They’re also hopeful that a legislative fix could be coming, with several bills pending as Democrats are in control of the House.

“But we’ve grown accustomed to not holding our breath,” Burge added.

Hudak is even less optimistic.

If Barr wanted to, Hudak said, he could “very quickly” approve applications for new growers. In Hudak’s view, the fact that Barr hasn’t taken action is at best a sign that it’s not a priority and at worst a sign that he’s against the effort.

And, given that many Republicans aren’t fans of marijuana legalization, Hudak doesn’t expect any major federal cannabis reform this session from the GOP-controlled Senate.

Meanwhile, cannabis researchers are plowing ahead.

Some, such as Arizona researcher Sue Sisley, are making due with the Ole Miss supply. Sisley recently completed the first randomized controlled trial of whole plant marijuana as a treatment for post-traumatic stress disorder (PTSD) in veterans. Results from that study should be published later this year.

Others are finding workarounds. In the fall, UC San Diego was given permission from the DEA to import cannabis capsules from Canada for a planned clinical trial on the use of marijuana to treat essential tremors.

But California is also taking longer than expected to start doling out $10 million in marijuana tax revenue that’s pledged to fund grants used by state universities conducting cannabis research projects.

The Bureau of Cannabis Control was expected to start awarding those funds months ago. But bureau spokesman Alex Traverso said Tuesday that they’re still working on getting the application process together.

So long as the government keeps dragging its feet, Hudak said, the public won’t have access to the type of “gold standard research” needed to make informed decisions about marijuana.