Why was Polk willing to risk war over California but not Oregon?

Answer 1

Because of money... Polk knew that California was needed as a way to monopolize trade with Asia and soon after the annexation of Texas and Mexican-American War was won this problem was solved but, both nations the United States and the United Kingdom claimed the Oregon region based on earlier exploration and the"right of discovery", described as "joint occupancy," making any resolution of the territorial and treaty issues until a later time. However later failed to settle upon a compromise boundary because British wanted to keep their fur trade South of the Columbia River for their powerful/profitable trading companies and the Oregon Dispute became important between the British Empire and the new American Republic. It was urged by the Democratic party for Polk to negotiate a boundary with the British because of "Manifest Destiny" era of the US. Polk accepted a compromise along the 49th parallel and it is still the boundary between the United States and Canada today..