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.