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In 1926, Mrs. Lucy Peabody of the Women's National Committee for Law Enforcement testified before Congress that the 18th Amendment and the laws passed to enforce it were "partially" successful based on various factors such as percieced improvemt in public health and morality, as well as the economy of the nation, among others; that the poor conditions of states (citing New York and Maryland) that failed to enforce Prohibition indicated the need for stronger enforcement of the law. LaGuardia, speaking before the same session of Congress on the opposite viewpoint, testified that it was "impossible" to judge the merits of Prohibition, good or bad, because it "has never been enforced in this country." He added. "There may not be as much liquor in quantity consumed to-day as there was before prohibition, but there is just as much alcohol," and cited several items of statistical evidence to support his claim. U.S. consumption of beverage alcohol, in gallons, according to the source I used for the above items, cannot be assessed because of the lack of data. Other sources seem to produce similar difficulties, but apparently cirrhosis deaths during Prohibition were lower that at any time before or after the period; on the other hand, they had been declining steadily since about 1908, and didn't begin to rise dramitically again until the late 1940s, so this factor is not necessarily relevant. Production of malt beverages in the U.S. decreased dramatically, from 28 million barrels in 1919 to 4.9 million in 1924, increased slightly in 1925, then declined to 2.8 million by 1932, then increased to 11 million in 1933, then 37.7 million in 1934, the year after the 21st Amendment was ratified. The Federal Council of Churches, of course, supported the 18th amendment on moral grounds and testified to Congress on the perceived success of Prohibition, arguing, "The evidence of history that other methods of attempting to control the traffic have failed and that prohibition, despite inadequacies of enforcement, is succeeding better than any other program." As to your questions based on the sources, I have cited them below for your reference (the ones I found, anyway). My own opinion is that Prohibition failed due to impossibility of enforcement on a national level; these results are indicative of what happens when activists of any political stripe try to manipulate the Constitution and government policy to affect social "reform." The 21st Amendment states, "The eighteenth article of amendment to the Constitution of the United States is hereby repealed," (Section 1) and, "The transportation or importation into any State, Territory, or possession of the United States for delivery or use there in of intoxicating liquors, in violation of the laws thereof, is hereby prohibited." (Section 2) It basically transferred the authority to enact and enforce Prohibition laws to the individual states and localities, where the authority actually belongs.