Alfred Thayer Mahan
The US naval officer whose 1890 book made 'sea power' the master key to national greatness and helped ignite the pre-1914 naval arms race.
Alfred Thayer Mahan was the American naval officer whose 1890 book taught the great powers that command of the sea was the master key to national greatness, and who then watched them race to build the fleets he had described. 'The Influence of Sea Power upon History, 1660–1783' has a strong claim to be the most consequential book an American strategist ever wrote: it helped drive the naval arms race that carried the world toward the First World War.
The argument
Mahan (1840–1914) grew up at West Point, where his father Dennis Hart Mahan was the US Army's most famous professor of engineering. His own career was spent at sea, a place he disliked and where he earned a name for steering ships into collisions; his real gift was analytical. Teaching at the new Naval War College in Newport, which he led from 1886 to 1889 and again in 1892 and 1893, he assembled a theory out of British history. Nations grow rich on seaborne trade, trade depends on secure sea lanes, and secure sea lanes require a battle fleet strong enough to win 'command of the sea'. He catalogued the ingredients a sea power needs, among them geographic position, a serviceable coastline and harbors, the size and seafaring temper of the population, and a government with the will to fund a navy.
Fleets, not raiders
Mahan's central operational claim was that a navy should never fritter its strength on raiding enemy merchant ships, the old guerre de course. It should mass its capital ships into one overwhelming fleet and seek a single decisive battle to annihilate the enemy's, as Nelson had at Trafalgar. Destroy the other side's fleet and you own the ocean and everything moving on it. Within a generation this was doctrine in half the navies on earth.
The book that built navies
It arrived at the perfect moment. Theodore Roosevelt, who met Mahan in 1888, drove the buildup that produced the Great White Fleet he sent around the globe from 1907. In Germany, Kaiser Wilhelm II said he was 'devouring' the book and trying to learn it by heart, and Admiral Tirpitz handed out 8,000 copies to sell the Reichstag on a High Seas Fleet, opening the dreadnought race with Britain. The Imperial Japanese Navy adopted Mahan as a textbook, and his cult of the decisive battle ran straight from the triumph at Tsushima in 1905 to catastrophe at Midway in 1942. He left a lighter mark on the map's vocabulary too: a 1902 article on the Persian Gulf popularized the phrase 'the Middle East'.
The echo
Carriers and submarines eventually retired Mahan's line of battleships, and rivals like Britain's Julian Corbett argued he overrated the single decisive clash. But his core proposition, that a trading superpower needs a navy able to control the sea lanes, still describes American grand strategy. The eleven US carrier strike groups, the global ring of bases, and the fixation on chokepoints from Hormuz to Malacca are Mahan rendered in steel. When American and Chinese warships shadow each other in the South China Sea, both fleets are reading from his book.