Question

what did John J. O'Sullivan write about?

Answer 1

He wrote about Manifest Destiny, which was the idea of America having a "divine right" to expand westward and claim the land for the US.

Answer 2

Hlee has returned. D: Manifest Destiny is a belief that it is U.S. destiny to conquer the west to the Pacific Ocean. Think about it. They were Native Americans living in the west. Instead of American saying 'We're going to steal the Native American's land and other territory's land because we want to' sounds like the Americans are the bad people. American saying 'It's our DESTINY to go west." sounds less evil.