Concept of U.S. territorial expansion westward to the Pacific Ocean.
The phrase was coined in 1845 by the editor John L. O'Sullivan, who described the U.S. annexation of Texas and, by extension, the occupation of the rest of the continent as a divine right of the American people. The term was used to justify the U.S. annexation of Oregon, New Mexico, and California and later U.S. involvement in Alaska, Hawaii, and the Philippines.