Not a government organisation, but there is a group of law enforcement officers advocating the end of the war on drugs. They don't seem to mention a specific type of narcotic, instead they refer to drugs in general. From their Wikipedia page:
The Law Enforcement Action Partnership (LEAP), formerly Law Enforcement Against Prohibition, is a U.S.-based 501(c)(3) nonprofit group of current and former police, judges, prosecutors, and other criminal justice professionals who use their expertise to advance drug policy and criminal justice solutions that enhance public safety.
One of their key issues, also from their Wikipedia page (emphasis is mine):
LEAP pushes to end the War on Drugs and legalize and regulate all drugs from a public health perspective as a means of reducing death, disease, and addiction associated with drug use and illegal drug sales.
Obviously, these people are not in charge of making the laws. Instead their jobs are enforcement-related. They are, however, familiar with the matter (given their professions) and as such it might be conceivable that their ideas spread to those who make the laws (possibly by shaping public opinion or through lobbying law makers).