Although the Union Navy's control of the American coastal and internal waterways was a decisive factor in the Civil War, its role in the Northern victory is still misunderstood. In order to assess that role, one must consider what would have happened had the South not only prevented or lifted the Union's blockade of southern ports, but mounted attacks against or blockaded northern ports.
Northern naval superiority had three crucial effects upon the war. First, the North's naval blockade prevented the South from exercising its price-setting power in the market for raw cotton. Although some have contended that the demand for southern-grown raw cotton was destined to decline in the 1860's, a comprehensive examination of the evidence indicates that, in the absence of the blockade-induced shortage of raw cotton, the demand for southern-grown cotton would have continued to be robust and growing. Instead, the blockade constricted exports of raw cotton and suppressed revenue; actual southern revenue from raw cotton was reduced by up to $700,000,000 during the war. This revenue loss severely impaired the South's war-making ability, particularly its ability to acquire a first-class navy. Second, Federal control of the coastal waters and inland rivers impeded southern intra-regional movement of goods, cutting off needed supplies of beef and other foodstuffs from Texas and Florida to civilians and soldiers throughout the eastern Confederacy. Since the North's control of the American waters exerted such deleterious effects upon the southern economy, one should ask whether the North was vulnerable to attacks upon its economy. This leads to the third, and perhaps most important, effect of Federal naval superiority: preventing the South from mounting naval actions against northern ports. Such attacks would have created economic hardships and eroded support for the Lincoln administration and the northern war effort. Given these effects of northern naval superiority, it is hard to see how the North could have defeated the South without its possession of a superior navy. Finally, while the Confederacy never attained control of the American waters, the possibility is investigated in this dissertation.