It might well have been Lord Palmerston (twice Prime Minister of Britain, 1855- 58, 1859- 65, q.v.) who concreted this term, though gunboat diplomacy in its various forms has been with us for centuries. The term implies diplomacy backed up by the threat of force (a gunboat for example) between countries, one state half-drawing a sword from its scabbard while talking in measured terms with another. It is all about imposing the will, and GD as I will call it was the accepted political force mostly in the nineteenth century.
British myself, I am resigned to the fact that it was Great Britain which used this kind of diplomacy to the greatest effect until the beginning of the First World War, simply because she had a superior navy, which could coerce smaller, weaker nations – sometimes big ones – to bend to her will.
Prime Minister Lord Palmerston, for instance, when it was reported that a British subject with a business in Athens had been assaulted by a crowd and his commercial interests threatened, sent a warship of the Royal Navy into the Mediterranean with orders to open fire on the Greek capital if immediate recompense were not paid to the British subject. Needless to say, he received compensation double quick. Ld. Palmerston also used GD in negotiations with China during the Opium Wars (1839 – 42: 1856 – 60).
He sent sixteen warships to lay siege to Canton (now Guangzhou) with the same force to be applied to Nanjing as a second course if the first did not persuade the Chinese to allow the opening of further ports to international trade (Great Britain). When this did not work Pekin (now Beijing) was occupied and by 1900 over fifty Chinese ports were doing trade with the world, though Palmerston was long dead.
In 1882 a British fleet fired cannon at Alexandria (Egypt) in order to crush a nationalist movement. The British were ‘ruling’ the country at the time through the Agent and Lord Cromer, and by 1900 Egypt had become a Protectorate (semi-independent but part of the Empire and defended by the Navy). In China in 1900 several powerful nations combined to protect their interests during the Boxer Rebellion and punish the rebels.
This was not popular with the Empress, but a combination of the USA, Britain, France and Germany was not to be taken lightly – gunboat diplomacy at its best.
The Americans used GD in the Philippines in 1898, and the same threat has been used by them on many occasions in Central and South America since, though it utterly failed in the Bay of Pigs disaster in Cuba in 1961, thanks to uncertain intelligence and faulty planning. American gunboat diplomacy was however highly successful in Morocco in 1907, when Marines from a US ship occupied Tangier because an American woman and her children had been kidnapped by a Rif ruffian.
The whole story can be seen in an excellent film called The Wind and the Lion with the brave sheik played with a Scottish accent by Sean Connery. This was gunboat diplomacy at its best. The occupation of a minute Spanish-owned island called Perejil by Morocco caused some more GD, this time from the Spanish Government and a Spanish warship.