Mahan, Alfred Thayer (1840–1914)

A late-19th-century American naval strategist and historian, Alfred Thayer Mahan is best known for his geostrategic writings on the geopolitical importance of sea power.

Born in New York in 1840, Mahan graduated from the U.S. Naval Academy and served as a captain in the U.S. Navy. In 1885, Mahan was appointed a lecturer at the Naval War College. Mahan's lectures served as the basis for his most influential work, his 1890 book, The Influence of Sea Power Upon History. Mahan argued that global geopolitical success was based on a country's sea power through its control of the oceans. Highlighting the importance of commerce and economic power, Mahan argued that a state needed a large powerful navy to protect and control commercial sea lanes. In Mahan's view, a country's potential sea power was based on a variety of factors, including its coastal physical geography (e.g., the length and nature of its coastline and harbors), the size of its population, and its national and governmental “character.”

Mahan's argument about the primacy of sea power was influential in policy circles both in the United States and abroad. His rise to prominence occurred in the late 19th and early 20th centuries during the height of European imperialism and as the United States was itself in the process of becoming an overseas empire.

Mahan's work both influenced and was influenced by American and European actions. As part of his call for American control of the seas, Mahan advocated the U.S. takeover of Hawaii, the Caribbean, the Philippines, as well as Panama to build a canal connecting the Atlantic and the Pacific Oceans. Mahan also promoted the buildup of the American Navy, as epitomized in President Theodore Roosevelt's construction of the “Great White Fleet.” His notoriety extended beyond policy circles to the general public through the many articles he wrote for popular American magazines of the time.

Beyond the United States, Mahan's writings also had important policy impact in the early 20th century. Mahan's work and policy proscriptions were important in England, Germany, and Japan, influencing naval buildups in these countries as well. Mahan is also credited with coining the regional designation term Middle East in 1902.

Mahan died in 1914 and is best remembered today within the history of early-20th-century geopolitics for his emphasis on the importance of sea power as juxtaposed to Halford Mackinder's land-based geopolitics.