The continuous friction led to a major civil war known as the Reform War from 1858 to 1860 and political instability, which the U.S. government under James Buchanan saw as a great opportunity to further expand the U.S. territory limits southwards (after the acquisition through war of California, Arizona, New Mexico, Nevada, Utah, most of Colorado, south Wyoming, and a fraction of Kansas and Oklahoma. For this reason and based upon the Doctrine Monroe, the U.S government sent an emissary to discuss with Juarez's liberal party the possibility to cede the Baja California peninsula to the United States, which he promptly accepted in exchange of diplomatic, economic and military support to counteract the conservative power that at that point, had the full support of the majority of the Mexican people, and was in control of the entire country with the exception of the cities of Morelia and Veracruz.