The historic marijuana bill debuted by three senators Tuesday is one small step for marijuana patients and one giant leap for science.

The Compassionate Access, Research Expansion, and Respect States (CARERS) Act is a multi-pronged approach at easing the tension between states and the federal government. The foundation of it is simple: a proposal to reclassify marijuana from a Schedule I substance (like heroin) to a Schedule II substance (like Adderall).

Supported by Senators Rand Paul, Kirsten Gillibrand, and Corey Booker, the bill would render the hyper-restrictive Controlled Substances Act (CSA) inapplicable to individuals who legally medicate with marijuana and the dispensaries who provide it. If passed, it would permit the 23 states (and the District of Columbia) where medical marijuana is legal to enforce the laws they’ve passed without fear of prosecution.

Beyond shielding the patients, doctors, and distributors from archaic laws, the bill would open the door to medical research on the drug that has been banned for decades.

Under the DEA’s current structure, testing Schedule I substances is near impossible. In two decades, just 15 researchers in the U.S. have made it through the process to gain approval. Even if a research is granted permission to test (which many cannot even procure the huge funds necessary to apply), another huge hurdle awaits.

As of today, the National Institute on Drug Abuse (NIDA) is the only entity with the power to provide cannabis for testing. The organization, devoted to stopping drug abuse, is a reluctant provider. The team maintains just one cannabis grow center, at the University of Mississippi, and its small marijuana crops produce low-grade, freeze-dried cannabis that is often unsuitable for testing.

Dr. Sue Sisley, the only researcher in the U.S. with permission to test cannabis, has lived through this research nightmare. After receiving approval to test marijuana on veterans with PTSD, she was swiftly fired from the University of Arizona (where the study was to be conducted) because of the stigma surrounding it. After moving the study to Colorado, she ran into more trouble, unable to procure two of the four plants she needed. Without this crucial piece of the study, Sisley was forced to move it to Israel, where she was located when news of the bill arrived.

The news was exciting to Sisley, who was particularly interested in the provision to amend the research process. If passed, the bill would nominate other entities (instead of just NIDA) to issue test-grade cannabis and end the public health service review that obstructs the approval process. In other words, if the bill passes, stories like Sisley’s will be history. While she’s hopeful this will pass, she’s all too aware of what we’ve lost in the waiting period. In the years since she began her study, aimed at helping veterans cope with their return, more than 24,000 of them have committed suicide.

Still, the news is huge.

The ability to perform large-scale, efficient tests of how humans react to cannabis would allow researchers to present hard evidence to Congress that the drug has medical value. It’s the lack of this hard data, in many ways, that is standing in the way of full legalization. Clear data on the positive effects of cannabis—and just as importantly, the negative ones—would lay the groundwork for a safe legalization of a drug that many researchers have already theorized is safer than alcohol.

At the press conference announcing the bill Tuesday, Sen. Paul touched on the importance of this step. “Is the proof [that marijuana has medical benefit]? We don’t know because there is no research,” said Paul. “I’m in favor of the research. I think this is an example of how Washington works.”

Dan Riffle, director of federal policies for the Marijuana Policy Project, was an integral part of getting the legislation onto the desks of the senators involved. As an adviser for the bill, he too points to the research concept as one of the key points. “That provision is more important than rescheduling,” he tells me. “Researchers will be able to do genetic engineering targeted for this specific patient, just like every other drug.”

But while Riffle and his team have spent years pushing for this change, it’s the senators behind it that he applauds today. “We’ve heard Sen. Cruz and Rubio say that states should be able to determine their own marijuana laws. They say it because they know it’s politically popular,” he says. “But kudos to Rand Paul, because it’s one thing to say it and its another to actually do something about it.”

At the Tuesday press conference, Sen. Gillibrand echoed the sentiments of Paul, introducing a young girl who has successfully stopped her seizures with the use of CBD oil. “These laws severely restrict scientific research of medical marijuana,” said Gillibrand. “This is clearly a case of ideology getting in the way of scientific process.”

Multiple medical marijuana patients took the stand to testify as to the quality of life improvement they’ve experienced with cannabis. One such patient, a mid-30-year-old with multiple sclerosis, said the medicine is an “answer to [her] prayers.” But as a resident of New Jersey, where the medical marijuana program is stalling, she’s been unable to procure it. “There is an urgent need for this change,” she said. “People are not getting their medicine because of…fear. To me, that’s the real crime.”

Sen. Booker, a longstanding supporter of marijuana legalization, captured the inspiration behind the bill itself—one that may very well make history. “Today we join together to say enough is enough,” he said. “Seek[ing] to right decades of wrong.”