A
filibuster or
freebooter, in the context of foreign policy, is someone who engages in an (at least nominally) unauthorized military expedition into a foreign country or territory to foment or support a revolution. The term is usually used to describe
United States citizens who fomented insurrections in
Latin America in the mid-19th century (Texas, California, Nicaragua, Colombia), but is also applicable in the modern day. Filibuster expeditions have also occasionally been used as cover for government approved
deniable operations (see also
False flag). A notable late 20th Century example of this would be the Argentinian 'scrap metal merchants' who landed on South Georgia at the outset of the
Falklands War.