Can law alone transform human behaviour? The American Prohibition experiment sought to eradicate alcohol through legislation, education, enforcement, and public campaigns, yet it ultimately failed. More than a thousand years earlier, Islam achieved what modern governments could not: the near-complete elimination of alcohol from society through faith-driven moral transformation. By comparing these two historical experiences, this study explores fundamental questions about law, morality, human psychology, social reform, and the relationship between Divine Revelation and human legislation. The analysis uncovers three universal principles that illuminate not only temperance laws but the entire structure of jurisprudence and ethics.