What did John O'Sullivan mean when he used the phrase "manifest destiny"?

John O'Sullivan first used the term in 1845 in an article for the Democratic Review. In his article, he argued for the United States to annex the Republic of Texas because the United States had a divine purpose to spread across the entire continent. At the time, the nation was in the midst of a fierce debate over the direction of the nation. Many Democrats, of which O'Sullivan was one, advocated a vision first...

John O'Sullivan first used the term in 1845 in an article for the Democratic Review. In his article, he argued for the United States to annex the Republic of Texas because the United States had a divine purpose to spread across the entire continent. At the time, the nation was in the midst of a fierce debate over the direction of the nation. Many Democrats, of which O'Sullivan was one, advocated a vision first articulated by Andrew Jackson which was rooted in conquest and territorial expansion. On the other side, Whigs advocated moral and social reform, not imperialism, and therefore opposed annexing Texas and the war with Mexico. Abraham Lincoln, who was a young lawyer at the time, fell into this camp.

O'Sullivan believed the United States had a destiny not only to spread its borders but to bring its people and to "civilize" the lands inhabited by Indians and Mexicans by spreading liberty through representative government.