IT WOULD BE difficult to deny that the efforts and resources expended in our attempt to prevent the production of heroin and cocaine in other countries, and to keep out of the United States those drugs that are produced, have passed the point of diminishing returns. The outcry over drugs in the newspapers and on the political hustings, and a look at what is occurring in many public-housing projects and in the large lower-class black and Hispanic neighborhoods of our central cities, should be enough to convince sober observers that our present drug policies have simply not been successful enough.