History shows us that economics are the driving force behind American politics. Prior to the creation of income tax, liquor taxes accounted for one-third of the annual revenue. In 1913 the national income tax was created, turning into the most lucrative revenue source for the U.S. Though religious groups had lobbied against the right to consume alcohol for decades, it was not until 1920, largely thanks to the country's new source of revenue, when the prohibition argument was seriously considered and alcohol was outlawed with the addition of the 18th Amendment.