In international politics, gunboat diplomacy (or "Big Stick ideology" in U.S. history) refers to the pursuit of foreign policy objectives with the aid of conspicuous displays of naval power—implying or constituting a direct threat of warfare, should terms not be agreeable to the superior force.
The term comes from the nineteenth-century period of imperialism, when Western powers - Europe and the United States - would intimidate other, less powerful states into granting concessions through a demonstration of their superior military capabilities, usually depicted by their naval assets. . A country negotiating with a Western power would notice that a warship or fleet of ships had appeared off its coast. The mere sight of such power almost always had a considerable effect, and it was rarely necessary for such boats to use other measures, such as demonstrations of cannon fire.
A notable and controversial example of gunboat diplomacy was the Don Pacifico Incident in 1850, in which the British Foreign Secretary Lord Palmerston dispatched a squadron of the Royal Navy to blockade the Greek port of Piraeus in retaliation for the harming of a British subject, David Pacifico, in Athens, and the subsequent failure of the government of King Otto to compensate the Gibraltar-born (and therefore British) Pacifico.
The effectiveness of such simple demonstrations of a nation's projection of force capabilities meant that those nations with naval power, especially Britain, could establish military bases (for example, Diego Garcia) and arrange economically advantageous relationships around the world. Aside from military conquest, gunboat diplomacy was the dominant way to establish new trade partners, colonial outposts, and expansion of empire.