Pamela Herr, "Frémont, John Charles," American National Biography Online, February 2000, http://www.anb.org/articles/05/05-00252.html.
When confirmed reports of war with Mexico reached the Pacific, the U.S. Navy seized California ports. Commodore Robert F. Stockton named Frémont commander of the California Battalion, which helped to occupy the province. In the winter of 1846-1847, during a revolt centered in Los Angeles, Frémont became entangled in a quarrel between Stockton and late-arriving General Stephen Watts Kearny of the army, both of whom claimed supreme authority in California. When Frémont, an army officer, rashly sided with Stockton, who had named him governor, Kearny marched him east in disgrace to face a court-martial. Despite widespread public support and Benton's personal defense of him during the long, rancorous trial, Frémont was found guilty and dismissed from the army. Although President Polk reinstated him for "meritorious and valuable services," Frémont bitterly resigned.