This is something that has always confused me. In 1919 the US Constitution was amended to ban alcohol. That amendment was repealed in 1933. Then in 1970 an act of Congress banned a large number of drugs, without a constitutional amendment. Numerous subsequent acts have added additional substances to the list.
Was a constitutional amendment actually necessary for the federal government to ban alcohol?
If so: Why was one unnecessary to ban and control hundreds of other substances, fifty years later?
If not: Why was a constitutional amendment used in 1919 instead of an ordinary law?