(One) That in the 1915 Congressional elections, the Anti-Saloon League swept in their candidates, so that there was a great legislative pressure to "do something."
(Two) Three that one of the key reasons the Anti-Saloon League was so potent was due to hatred of the Germans, the war-time enemy. Germans were closely associated with the Beer Trade.
(Three) the Cato Institute put the following apt poem up:
Prohibition is an awful flop.
We like it.
It can't stop what it's meant to stop.
We like it.
It's left a trail of graft and slime,
It don't prohibit worth a dime,
It's filled our land with vice and crime.
Nevertheless, we're for it.—Franklin P. Adams (1931)
And there's a nugget of GOLD with those two gems ... the Cato Institute's study continues:
History of ProhibitionIf the value of drug prohibition is not self-evident,one might ask why it was put into effect in the first place.Drugs in one form or another were in effect legal for thousands of years before the Harrison Act of 1914, but the period of greatest availability in the United States was the 19th century. For most of the century, opium, morphine, and cocaine were legally and cheaply available without a prescription at drugstores and grocery stores and through the mail.[8] And yet, far from being marked by drug-crazed criminals and drug-paralyzed workers, that period was a time of unprecedented economic growth and productivity.
Regarding the impact of pre-prohibition drug use in theUnited States:
There was very little popular support for a law banning [narcotics]. "Powerful organizations for the suppression of alcoholic stimulants exist throughout the land" [citation omitted], but there were no similar anti-opiate organizations. The reason for this lack of demand for opiate prohibition is simple: the drugs were not viewed as a menace to society and . . . they were not in fact a menace.[9]The situation in l9th-century England was remarkably similar:Consumption under conditions of free supply in effect plateaued out. . . . Incapacity from use of opium was not seen as a problem of such frequency and severity as to be a leading cause for social anxiety.The prime image of the opium user was dissimilar to that of the wastrel and disruptive drunkard. Opium users were not lying about in the streets, or filling the workhouses, or beating their wives. It seems fair to conclude that at the saturation level which the plateau represented, opium was not a vastly malign or problematic drug in terms of its impact on social functioning.[10]If there was no catastrophic drug problem before prohibition, why then was the Harrison Act enacted? In 1926, after11 years of narcotics prohibition, an editorial in the Illinois Medical Journal stated:
The Harrison Narcotic law should never have been placed upon the statute books of the United States. It is to be granted that the well-meaning blunderers who put it there had in mind only the idea of making it impossible for addicts to secure their supply of "dope" and to prevent unprincipled people from making fortunes, and fattening themselves upon the infirmities of their fellow men. As is the case with most prohibitive laws, however, this one fell far short of the mark.So far, in fact, that instead of stopping the traffic, those who deal in dope now make double their money from the poor unfortunates upon whom they prey. . . .The doctor who needs narcotics, used in reason to cure and allay human misery, finds himself in a pit of trouble. The lawbreaker is in fact in clover. .. . It is costing the United States more to support bootleggers of both narcotics and alcoholics than there is good coming from the farcical laws now on the statute books.As to the Harrison Narcotic law . . . people are beginning to ask, "Who did that, anyway?"[11]The most important "who" was Secretary of State William Jennings Bryan:
A man of deep prohibitionist and missionary convictions and sympathies, he urged that the law be promptly passed to fulfill United States obligations under the new international [drug control] treaty. The supporters of the Harrison bill . . . said little about the evils of narcotics addiction in the United States. They talked more about the need to implement the Hague Convention of 1912. . . .Far from appearing to be a prohibition law, the Harrison Narcotics Act on its face was merely a law for the orderly marketing of opium, morphine, heroin, and other drugs--in small quantities over the counter, and in larger quantities on a physician's prescription. . . . It is unlikely that a single legislator realized in 1914 that the law Congress was passing would later be deemed [by the courts] a prohibition law.[12]Two other reasons for the passage of the Harrison Act were the association of opium and its derivatives with the scorned minority of Chinese Americans,[13] and the lobbying of physicians and pharmacists eager to gain a legal monopoly over distribution of the prescribed drugs.[14]As for marijuana, when it was banned in 1937, no medical testimony was presented to Congress.[15] Drug prohibition was thus not based upon even a semblance of analysis and research.
Be that as it may, there were other reasons for restricting drugs. Not mentioned by you were the drug addictions caused by "elixers" containing opiates, a big problem. But no sense in me getting into all that, since you know what will happen.