I’m not sure, sorry but i hope you get it right
The correct answer is The Oregon Territory.
That territory was into the dispute of British and Americans because of the Hudson Bay and the deep sea ports. In 1820 California Trails were built and Americans expanded even more westward. The British would not give up on the territory without a fight. This became a political issue. Because of that the slogan “54-40 or fight!” came up. 54 meant the 54th parallel and the boundary the Americans would accept.
Yugoslavia. Yugoslavia was only a member for 2 days
