After almost a year in office, the Obama administration made a decision this week.

The Justice Department ... issued a memo to federal prosecutors in Colorado and 12 other medical marijuana states telling them to stop enforcing federal marijuana laws against medical marijuana patients. This should result in an end to the mean-spirited and bizarre federal attacks on people treating conditions such as glaucoma and chronic pain with a natural drug that’s far less harmful than an array of hard drugs the pharmaceutical giants push like candy.

From the memo: ‘‘Prosecution of individuals with cancer or other serious illnesses who use marijuana as part of a recommended treatment regimen consistent with applicable state law, or those caregivers in clear and unambiguous compliance with existing state law who provide such individuals with marijuana, is unlikely to be an efficient use of limited federal resources.’’ ...

Although the memo was clear in directing federal authorities to respect state medical marijuana laws, it emphasized the federal government’s commitment to continuing the drug war. Prohibition has created a black market, in the form of Mexican cartels that are willing to kill in order to trade in common weed.

The administration’s memo is a step in the direction of ending prohibition. It’s a small step, but first steps are milestones.