What was one argument supporting the claim that the Mexican-American War was 'Mr. Polk's War'?

The assertion that the Mexican-American War was 'Mr. Polk's War' is grounded in President James K. Polk's aggressive approach toward Mexico and his support for the annexation of Texas. Polk was a staunch advocate for Manifest Destiny, the belief that the United States was destined to expand across the North American continent. His administration was characterized by a strong push to acquire not only Texas but also other territories in the West.

Polk's actions, such as sending troops to the disputed border between Texas and Mexico and his willingness to engage in military conflict, demonstrate his hardline stance. This militaristic approach, aimed at seizing land from Mexico, provides a clear link to the characterization of the war as his initiative. While some might argue that other presidents or political factions had influences during this time, it was Polk's direct involvement and policy decisions that framed the war and led to a significant expansion of U.S. territory.