Polk's administration aimed to resolve which of the following issues with Britain?

Polk's administration focused significantly on border disputes with Britain, primarily concerning the Oregon Territory. During Polk's presidency in the mid-19th century, tensions were high over the boundary between British Canada and the United States in the Pacific Northwest. The slogan "54°40' or Fight!" captured the urgency and assertive stance many Americans took regarding the territorial claim that included a northern latitude line, pushing for U.S. expansion.

Ultimately, Polk negotiated a peaceful resolution, leading to the Oregon Treaty of 1846, which established the border at the 49th parallel, effectively resolving this long-standing dispute without resorting to conflict. This aspect of Polk's foreign policy was not just about territory but also reflected the broader American ethos of Manifest Destiny, the belief that the U.S. was destined to expand across the North American continent.