Newspaper editor John O'Sullivan is generally credited with coining the term manifest destiny in 1845 to describe the essence of this mindset, which was a rhetorical tone; however, the unsigned editorial titled "Annexation '' in which it first appeared was arguably written by journalist and annexation advocate Jane Cazneau. The term was used by Democrats in the 1840s to justify the war with Mexico and it was also used to divide half of Oregon with the United Kingdom. But manifest destiny always limped along because of its internal limitations and the issue of slavery, says Merk. It never became a national priority. By 1843, former U.S. President John Quincy Adams, originally a major supporter of the concept underlying manifest destiny, had changed his mind and repudiated expansionism because it meant the expansion of slavery in Texas.
in which war was manifest destiny used to justify united states government actions
war with Mexico