Question

According to Document 4, why does President Polk think the U.S. should extend its borders?

Answer 1

Polk was a massive supporter for Manifest Destiny, so an encouragement for expansion was something he definitely wanted. Not to mention the conflict over Texas with Mexico. Even more so, the conquest of California was a dream for many Americans, something that was theirs to be taken and that would lead the U.S to expand into the Pacific, and Polk was a big supporter.