I'll be honest with you. It was a total guess based on your sense of irony. Also, my knowledge of the history of illicit substances is not that great.

Hmm. Seems that the first drugs law in the US was a New York state alcohol prohibition in 1845. Then localized opium-smoking prohibitions in the 1870s, mostly directed at Chinese immigrants. The first national prohibition seems to have been 1914's Harrison Tax Act, outlawing opiates and cocaine.

Of course, the issue was trafficking, which may have been illegal elsewhere....