The Volstead Act was a hopeless piece of legislation, in that it didn't take into account the willingness and ingenuity of regular citizens and lawbreakers to get around the feeble enforcement provisions. The "Drys" naively assumed that the "Wets" would actually honor the law.
On the night of 16 January, 1920, the level of drinking by the nation's "Wets" was somewhat muted. On 17 January, the celebration of the "Drys" was off-the-charts; it was vitriolic and self-congratulatory hyperbole . . . to the "Drys", they had totally defeated the "Wets"; those that consumed alcohol had become a "conquered people".
Adding to the future futility of enforcing Prohibition was Wayne Wheeler's idea to put the agents in the Prohibition Bureau under the authority of the Treasury Department, not under Justice (Wheeler had lobbied Ohio Senator Warren Harding very hard for that decision). Very early, that proved to be a disastrous decision, in that since the agents were civil servants, they were poorly paid and equipped . . . the conditions were ripe for corruption at the enforcement level in the federal government during Prohibition.
The ingenuity of clandestine liquor manufacturers / brewers was impressive; it was worth their while to supply that product, in that demand for illegal alcohol was sky-high. Defying Prohibition became the "thing to do" with college students, "Flappers", and much of America's middle class (also, the cocktail was invented during Prohibition, in order to disguise the taste of bad liquor).
Below: America's most famous columnist, H.L Mencken of the Baltimore Sun,
openly and enthusiastically violating Prohibition in a speakeasy.
(Below: A segment from Ken Burns' "Prohibition",
tracing the last few years before the 18th Amendment)