There was quite a lot of alcohol drunk in the US in the early days of the republic. When you look at old ledgers you will find constant regular sales of rum, whiskey and brandy. De Toqueville noted that every interaction seemed to be accompanied by a drink. Men had the most opportunities to drink and the most encouragement to drink, and so alcohol was seen as a danger to domestic life, something that wrecked marriages, and homes. As married women had few rights and could not easily obtain a divorce, not surprisingly, temperance groups were strongly associated with women: the Daughters of Temperance, the Women's Christian Temperance Union. They attracted women like Susan B Anthony, who were interested in advancing women's rights. And they also adopted other moral causes, like the abolition of slavery.
The industrialization of the US created even more male alcoholism. Working hours at a factory were long, wages were generally low, and in many places a man coming home from his job with his wages in his pocket would walk by several saloons.Even in the rural US, miners, lumbermen, cattle hands would be living in isolation with few activities for their free time, other than drinking. Rather than looking at the host of problems (especially the low wages) more and more people focused on alcohol. It was a moral cause that could be preached, with sinners to be saved and villains ( saloon owners, brewers and distillers) to be denounced.
However great the problem, though, most people still thought it was OK to have a drink. Also, the temperance groups had adopted a wide range of progressive issues, so a politician who was not in favor of banning alcohol but was progressive in other ways would still get their votes. This changed with the advent of Wayne Wheeler and the Anti Saloon League. The ASL created beautiful parades of young women and girls in white, carrying banners. They got the endorsement of many churches. And, most importantly, they only cared about their single cause of banning alcohol: if a politician signed up with them, they voted for him. If he did not, they worked to elect his opponent. It was the beginning of single-issue advocacy, and it was devastatingly effective. The opposition to Prohibition was, on the other hand, quite disorganized. Brewers, saloon owners, distillers and drinkers had nothing to equal the ASL.
So, there was a wave of legislation, the Volsted Act was passed. And, as I said, since most people were not against having a drink now and then, there was massive non-compliance. Worse, drinking became fashionable. Instead of shameful and sad, drunks were funny and adorable ( watch one of the Thin Man movies). Saloons and bars had previously been male establishments- women who drank in them were considered prostitutes. With drinking fashionable, for the first time women could go into bars and drink without shame- and it was discovered that women could be alcoholics as well as men. Prohibition, it quickly became obvious, wasn't prohibiting at all. With the onset of the Great Depression, it was finally possible for the opposition to get organized and to be heard, often with the simple message, times are hard, why not let the working man have his beer?
Although Wayne Wheeler would not live to see the end of Prohibition, the single issue advocacy that he pioneered was later used to great effect, notably by anti-abortion groups and the NRA. And like Prohibition, the effect tended to be divisive.
The story is quite well told in Daniel Okrent's Last Call, which Ken Burns used as the basis for his film on the subject.
Should it also be noted that Prohibition came into law during the early success of anti-immigration forces? Although drinking was common from the country’s earliest days, it was increasingly associated with Catholic immigrants — Irish, Italians, Slavs. At least as early as 1884, presidential candidate James Blaine’s hope of wooing Irish voters was crushed when a Protestant minister speaking in his favor warned of “rum, Romanism and rebellion.”
Blue laws banning business — and especially alcohol sales — on Sundays were a frequent battleground between WASPs and Catholic immigrants. William Jenkins’ “Steel Valley Klan” explains how the KKK exploited this in Ohio’s Mahoning Valley. Blue laws and other restrictions on drinking — in public, anyway — were a proxy for discouraging Southern and Eastern Europeans.
Daniel Okrent’s “The Guarded Gate” traces the growing power of the anti-immigration movement, showing that it was really a White Power movement (for a very limited definition of “white.”) After years of near-misses, the movement had its first real successes in the ‘Teens.
Remember, The Constitution is not amended by popular vote. Then, as now, state legislatures are subject to intense political machinations that have tended to disfavor urban areas — bedrock of Irish and other “ethnics” — while overrepresenting rural voters.
As for Prohibition’s unpopularity — that would have come from those truly affected. I’m guessing — perhaps someone more familiar with the period can comment — that the upper class, leaders of the anti-immigration movement, would scarcely have noticed things drying up, between their stocked cellars, speakeasies and cowed cops. It was those unwanted immigrant working classes who found the spigots turned off.