How does the author suggest that Manifest Destiny is not as noble as Cordelia makes it out to be?

As the manifest destiny is a belief that states it was God's will that Americans spread over the entire continent, and to control and populate the country as they see fit. in fact, it was used before civil war to validate the acquisition of continental territories like oregon, for example. This is the central idea that the author suggests by Cordilia's ideas in her letter.