Who was the U.S. president in 1845 who aimed to resolve the Oregon boundary dispute and expand the nation?

James K. Polk was the U.S. president in 1845 who focused on territorial expansion and aimed to resolve the Oregon boundary dispute. During Polk's administration, he strongly encouraged the concept of Manifest Destiny, the belief that the U.S. was destined to expand across the North American continent. This expansionist vision was evident in his negotiations concerning the Oregon Territory, where he sought to settle the border dispute with Britain. Ultimately, Polk's approach led to the Oregon Treaty of 1846, which established the 49th parallel as the boundary between U.S. and British territories in the region.

Polk's aggressive stance on expansion also included the annexation of Texas and the initiation of the Mexican-American War, further demonstrating his commitment to expanding U.S. territory. His presidency was marked by significant territorial acquisitions that shaped the future of the nation, making his choice as the correct answer in relation to the question.