In the July–August 1845 issue of the Democratic Review, John Louis O’Sullivan published an essay entitled “Annexation,” advocating that the U.S. admit the Republic of Texas into the Union. O’Sullivan argued that the United States had a divine mandate to expand throughout North America, writing of “our manifest destiny to overspread the continent allotted by Providence for the free development of our yearly multiplying millions.”
The phrase didn’t really catch on however until another article of O’Sullivan’s appeared in the “New York Morning News” on December 27, 1845. In this instance, he was justifying the American claim to Oregon, averring:
…that claim is by the right of our manifest destiny to overspread and to possess the whole of the continent which Providence has given us for the development of the great experiment of liberty and federated self-government entrusted to us.”
This is not the first time a religious justification had been used to support land expansion. John Quincy Adams firmly believed that territorial expansion across the whole continent of North America was “destined by Divine Providence.” As Secretary of State, his views helped guide the policies of President James Monroe. It was the diplomacy of Adams’ that was largely responsible for the U.S. acquisition of Florida and the U.S. assumption of Spain’s claim to the Oregon country. The 1823 Monroe Doctrine, formulated by Adams, warned Europe that the Western Hemisphere was no longer open for European colonization. However, Adams had not employed the catchy phrase, “manifest destiny.” Moreover, the possibility of a continental republic seemed much more possible in the 1840’s than it had earlier.