King Cotton was a slogan used by southerners (1860–61) to support secession from the United States by arguing cotton exports would make an independent Confederacy economically prosperous, and—more important—would force Great Britain and the France to support the Confederacy in the Civil War because their industrial economy depended on cotton textiles. The slogan was successful in mobilizing support: by February 1861, the seven states whose economies were based on cotton plantations had all seceded and formed the Confederacy. However, the other eight slave states remained in the Union. To demonstrate their economic power southerners spontaneously refused to sell or ship out their cotton in early 1861; it was not a government decision. By summer 1861, the Union blockade shut down over 95% of exports. Since the Europeans had large stockpiles of cotton, they were not injured by the boycott—the value of their stockpiles went up. To intervene meant war with the U.S. and a cutoff of food supplies, so Britain did not intervene. Consequently, the strategy proved a failure for the Confederacy—King Cotton did not help the new nation.
The South has long, hot summers, and rich soils in river valleys—ideal conditions to grow cotton. The drawback of growing cotton was mainly the time spent removing the seeds after harvest. Following invention of the cotton gin by Eli Whitney in 1793, cotton production surpassed that of tobacco in the South and became the dominant cash crop. At the time of the American Civil War, Southern plantations supplied 75% of the world's.
The insatiable European demand for cotton was a result of the Industrial Revolution. In Great Britain, a series of inventions resulted in the mechanized spinning and weaving of cloth in the world’s first factories in the north of England. The ability of these factories to produce unprecedented amounts of cotton cloth revolutionized the world economy, but Great Britain needed raw cotton.
British textile manufacturers were eager to buy all the cotton that the South could produce. Cotton-bale production supports this conclusion: from 720,000 bales in 1830, to 2.85 million bales in 1850, to nearly 5 million in 1860. Cotton production renewed the need for slavery after the tobacco market declined in the late 18th century. The more cotton grown, the more slaves were needed to pick the crop. By 1860, on the eve of the American Civil War, cotton accounted for almost 60% of American exports, representing a total value of nearly $200 million a year.
Without firing a gun, without drawing a sword, should they make war on us, we could bring the whole world to our feet... What would happen if no cotton was furnished for three years?... England would topple headlong and carry the whole civilized world with her save the South. No, you dare not to make war on cotton. No power on the earth dares to make war upon it. Cotton is King.
Southerners thought their survival depended on the sympathy of Europe to offset the power of the Union. They believed that cotton was so essential to Europe that they would intervene in any civil war.
British position 
When war broke out, the Confederate people, acting spontaneously without government direction, held their cotton at home, watching prices soar and economic crisis hit Britain and New England. Britain did not intervene because it meant war with the United States, as well as loss of the American market, loss of American grain supplies, risk to Canada, and much of the British merchant marine, all in the slim promise of getting more cotton. Besides that, in the spring of 1861, warehouses in Europe were bulging with surplus cotton—which soared in price. So the cotton interests made their profits without a war. The Union imposed a blockade, closing all Confederate ports to normal traffic; consequently, the South was unable to move 95% of its cotton. Yet, some cotton was slipped out by blockade runner, or through Mexico. Cotton diplomacy, advocated by the Confederate diplomats James M. Mason and John Slidell, completely failed because the Confederacy could not deliver its cotton, and the British economy was robust enough to absorb a depression in textiles from 1862–64.
As Union armies moved into cotton regions of the South in 1862, the U.S. acquired all the cotton available, and sent it to Northern textile mills or sold it to Europe. Cotton production increased in India by a factor of 700% and also increased in Egypt.
When war broke out, the Confederates refused to allow the export of cotton to Europe. The idea was that this cotton diplomacy would force Europe to intervene. However, European states did not intervene, and following Abraham Lincoln's decision to impose a Union blockade, the South was unable to market its millions of bales of cotton. The production of cotton increased in other parts of the world, such as India and Egypt, to meet the demand. A British-owned newspaper, The Standard of Buenos Aires, in cooperation with the Manchester Cotton Supply Association succeeded in encouraging Argentinian farmers to drastically increase production of cotton in that country and export it to the United Kingdom.
Surdam (1998) asks, "Did the world demand for American-grown raw cotton fall during the 1860s, even though total demand for cotton increased?" Previous researchers have asserted that the South faced stagnating or falling demand for its cotton. Surdam's more complete model of the world market for cotton, combined with additional data, shows that the reduction in the supply of American-grown cotton induced by the Civil War distorts previous estimates of the state of demand for cotton. In the absence of the drastic disruption in the supply of American-grown cotton, the world demand for such cotton would have remained strong.
Lebergott (1983) shows the South blundered during the war because it clung too long to faith in King Cotton. Because the South's long-range goal was a world monopoly of cotton, it devoted valuable land and slave labor to growing cotton instead of urgently needed foodstuffs.
See also 
- Frank Lawrence Owsley, King Cotton Diplomacy: Foreign relations of the Confederate States of America (1931)
- Yafa (2004)
- TeachingAmericanHistory.org "Cotton is King" http://teachingamericanhistory.org/library/index.asp?document=1722
- Eli Ginzberg, "The Economics of British Neutrality during the American Civil War," Agricultural History, Vol. 10, No. 4 (Oct., 1936), pp. 147–156 in JSTOR
- Charles M. Hubbard, The Burden of Confederate Diplomacy (1998)
- Argentina Department of Agriculture (1904), Cotton Cultivation, Buenos Aires: Anderson and Company, General Printers, p. 4, OCLC 17644836
- David Donald, Why the North won the Civil War (1996) p. 97
- John Ashworth, Slavery, capitalism, and politics in the antebellum Republic (2008) vol 2 p 656
- Blumenthal, Henry. "Confederate Diplomacy: Popular Notions and International Realities." Journal of Southern History 1966 32(2): 151-171. Issn: 0022-4642 in Jstor
- Hubbard, Charles M. The Burden of Confederate Diplomacy (1998)
- Jones, Howard, Union in Peril: The Crisis over British Intervention in the Civil War (1992) online edition
- Lebergott, Stanley. "Why the South Lost: Commercial Purpose in the Confederacy, 1861-1865." Journal of American History 1983 70(1): 58-74. Issn: 0021-8723 in Jstor
- Lebergott, Stanley. "Through the Blockade: The Profitability and Extent of Cotton Smuggling, 1861-1865," The Journal of Economic History, Vol. 41, No. 4 (1981), pp. 867–888 in JSTOR
- Owsley, Frank Lawrence. King Cotton Diplomacy: Foreign relations of the Confederate States of America (1931, revised 1959) Continues to be the standard source.
- Scherer, James a.b. Cotton as a world power: a study in the economic interpretation of history (1916) online edition
- Surdam, David G. "King Cotton: Monarch or Pretender? The State of the Market for Raw Cotton on the Eve of the American Civil War." Economic History Review 1998 51(1): 113-132. in JSTOR
- Yafa, Stephen H. Big Cotton: How A Humble Fiber Created Fortunes, Wrecked Civilizations, and Put America on the Map (2004)