Final answer:
President James K. Polk would indeed support Manifest Destiny, as his presidency was defined by aggressive expansionist policies resulting in the annexation of Texas and other territories, thereby shaping the U.S. into a transcontinental republic.
Step-by-step explanation:
President James K. Polk was a strong proponent of Manifest Destiny, believing it was the United States' divine right and duty to expand its territory across the continent. His presidency saw significant expansion with the annexation of Texas and the acquisition of Oregon and the Southwest following the war with Mexico, reflecting his aggressive expansionist policies.
The concept of Manifest Destiny justified such expansion as part of America's mission, portraying it as inevitable and divinely ordained. Polk's administration also fought to extend the nation's borders to the shores of the Pacific, fulfilling the expansionists' dreams by making the U.S. a republic from the Atlantic to the Pacific.