As far back as 1972, a federal report commissioned by President Richard Nixon recommended that marijuana use and possession be decriminalized, arguing that "neither the marihuana [sic] user nor the drug itself can be said to constitute a danger to public safety."
But Nixon ignored the report's findings. Marijuana was left on Schedule 1 of the Controlled Substances Act, the most restrictive category, reserved for drugs that "have no currently accepted medical use in the United States, a lack of accepted safety for use under medical supervision, and a high potential for abuse." Other Schedule 1 drugs include heroin and LSD.
And in that context, Rosenberg's cautious acknowledgement on the relative safety of marijuana is indeed news. It's a small sign that under its new leadership the DEA may start staking out policy positions that are more in line with the White House, Congress, and the American public.