 In 1855 , an Ohioan , David Christy , published Cotton Is King : or Slavery in the Light of Political Economy . Christy argued that the flow of cotton was so important to the industrialized world that cutting it off would be devastating — not least to the Northern United States , as cotton was by far the largest U.S. export . This became known as the " King Cotton " theory , to which Davis was an enthusiastic subscriber . Benjamin also spoke in favor of the theory , though Butler suspected he may have " known better " , based on his firsthand knowledge of Europe . 
