The controversy was eventually ended by the Mexican Cession, which added the territories of Alta California and Nuevo México to the United States, both more sparsely populated than the rest of Mexico. Like the All Oregon movement, the All Mexico movement quickly abated.
Historian Frederick Merk, in Manifest Destiny and Mission in American History: A Reinterpretation (1963), argued that the failure of the All Oregon and All Mexico movements indicates that manifest destiny had not been as popular as historians have traditionally portrayed it to have been. Merk wrote that, while belief in the beneficent mission of democracy was central to American history, aggressive "continentalism" were aberrations supported by only a minority of Americans, All of them Democrats, well it was opposed by Whigs and some Democrats. Thus the Democrats of Louisiana opposed annexation of Mexico,[50] while those in Mississippi supported it.[