This series was begun on Facebook, but was starting to feel too big for that platform. We will continue to copy posts to FB, but we're temporarily re-establishing Vox Populi for the remainder of the series.
James K. Polk was president from 1845 to 1849. For a one-term president Polk brought much change to the United States. Doing so risked war with two other nations.
Polk supported the doctrine of Manifest Destiny, the idea that America was destined to stretch from the Atlantic to the Pacific. The Oregon Territory, which comprised what are now the states of Oregon, Washington, Idaho, and parts of Wyoming and Montana, was jointly occupied by the United States and Great Britain, and Polk risked conflict with Britain by annexing the territory. Negotiations between the nations finally resulted in splitting the territory at the 49th parallel, establishing the southern boundary of Canada.
Polk also moved to annex Texas, which led to the Mexican War. When Mexico was defeated the terms of the treaty required that country to cede not only Texas, but also the territory that is now California, and parts of Arizona, Utah, New Mexico and Colorado.
Polk's term was politically controversial, but he achieved all his goals and set in motion events that would ultimately add ten states to the union. Not bad for a dark horse candidate from Tennessee.