Dr. Sanjay Gupta’s evolution on cannabis has been rather remarkable. In 2009, he was a prominent voice opposing legalization. By 2013, he had examined the issue more and publicized his change of heart with his first “Weed” special on CNN.

Dr. Gupta even issued an apology for his previous prohibitionist position on CNN.com:

I apologize because I didn’t look hard enough, until now. I didn’t look far enough. I didn’t review papers from smaller labs in other countries doing some remarkable research, and I was too dismissive of the loud chorus of legitimate patients whose symptoms improved on cannabis. Instead, I lumped them with the high-visibility malingerers, just looking to get high. I mistakenly believed the Drug Enforcement Agency listed marijuana as a schedule 1 substance because of sound scientific proof. Surely, they must have quality reasoning as to why marijuana is in the category of the most dangerous drugs that have “no accepted medicinal use and a high potential for abuse.” They didn’t have the science to support that claim, and I now know that when it comes to marijuana neither of those things are true. It doesn’t have a high potential for abuse, and there are very legitimate medical applications. In fact, sometimes marijuana is the only thing that works. Take the case of Charlotte Figi , who I met in Colorado. She started having seizures soon after birth. By age 3, she was having 300 a week, despite being on seven different medications. Medical marijuana has calmed her brain, limiting her seizures to 2 or 3 per month.

Dear Honorable Jeff Sessions, I feel obligated to share the results of my five-year-long investigation into the medical benefits of the cannabis plant. Before I started this worldwide, in-depth investigation, I was not particularly impressed by the results of medical marijuana research , but a few years later, as I started to dedicate time with patients and scientists in various countries, I came to a different conclusion.

*** The consensus is clear: Cannabis can effectively treat pain. The National Academies of Sciences, Engineering, and Medicine arrived at this conclusion last year after what it described as the “most comprehensive studies of recent research” on the health effects of cannabis. *** Recently, your fellow conservative John Boehner changed his mind after being “unalterably opposed” to marijuana in the past. If you do the same, Mr. Attorney General, thousands of lives could be improved and saved. There is no time to lose.

It is great that Dr. Sanjay Gupta is using his wide public platform to do as much to publicize the important benefits of medical cannabis as anyone today. Activists across the United States have done a great job legalizing medicinal use state after state, but we have to do so much more. While maintaining states’ rights on the issue, particularly the ability to have your own personal garden and safely produce your own products like medicated edibles, it is imperative that we legalize across the nation as Canada and Germany have done. Germany’s mandate that insurance providers must reimburse patients for cannabis is definitely a step needed in the United States. Patients and their doctors should be able to make the best decision, not Big Pharma. We have made such great progress, but we need to make more as people’s lives literally depend upon it.