Textbook:
For a quarter century after the War of 1812, only a few Americans explored the West. Then, in the 1840s, expansion fever gripped the country. Many Americans began to believe that their movement westward was predestined by God. The phrase "manifest destiny" expressed the belief that the United States was ordained to expand to the Pacific Ocean and into Mexican and Native American territory. Many Americans also believed that this destiny was manifest, or obvious and inevitable.

Document C: Parker Sermon

We treated Mexico contemptuously before hostilities began. We sent an army to invade her soil, to capture her cities, and to seize her territory. It has been a war of plunder, undertaken for the purpose of seizing Mexican territory and extend [slavery over the territory]. It was not enough to have Louisiana a slave territory; not enough to make that institution perpetual in Florida; not enough to extend this blight over Texas--we must have yet more slave soil, one day to be carved into slave states.

The war was unjust at its beginning; mean in its motives, a war without honorable cause, a quarrel between a great boy and a little puny weakling who could not walk alone and could hardly stand... Our contest has been like the English seizure of Ireland. All the Justice was on one side--the force, skill, and wealth on the other.

Does document C support or refute the textbook account? explain.