Final answer:
President Polk's plan was viewed as opportunistic due to his strategic and principle-flexible tactics to achieve U.S. territorial expansion, harnessing Manifest Destiny and igniting the Mexican-American War for territorial gain.
Step-by-step explanation:
To say that President Polk's plan was opportunistic means he took advantage of circumstances with little regard for principles or consequences. His actions, particularly in the annexation of Texas and the provocation of the Mexican-American War, were driven by a desire to expand U.S. territory.
Throughout his presidency, James K. Polk focused on expanding the U.S. to the Pacific. He exploited the concept of Manifest Destiny and the nation's expansionist mood. Polk's decision to move troops into contested territory with Mexico was a calculated move.
This spurred the onset of the Mexican-American War, ultimately leading to significant territorial gains for the United States but also exacerbating sectional tensions over slavery. His maneuvers were strategic, aimed at achieving his expansionist goals, and played a significant role in the growth of presidential war powers.
President Polk's eagerness to acquire land is seen by some as an expression of Manifest Destiny, while others criticize it as a mere facilitation of slaveholding interests. His legacy is hence marked by the dual nature of aggressive expansionism and the extension of executive powers.