Fifty-four forty or fight, in U.S. history, phrase commonly used by extremists in the controversy with Great Britain over the Oregon country. The rights of the United States, they maintained, extended to the whole region, i.e., to lat. 54°40'N, the recognized southern boundary of Russian America. It was used as a campaign slogan in the presidential election of 1844 by Democrat James K. Polk, who was elected.