William Walker (filibuster)

William Walker (May 8, 1824 – September 12, 1860) was an American journalist and mercenary. In the era of the expansion of the United States, driven by the doctrine of manifest destiny, Walker organized unauthorized military expeditions into Mexico and Central America with the intention of establishing colonies. Such an enterprise was known at the time as "filibustering".

After settling in California, motivated by an earlier filibustering project of Gaston de Raousset-Boulbon, Walker attempted in 1853–54 to take Baja California and Sonora. He declared those territories to be an independent Republic of Sonora, but he was soon driven back to California by the Mexican forces. Walker then went to Nicaragua in 1855 as leader of a mercenary army employed by the Nicaraguan Democratic Party in its civil war against the Legitimists. He took control of the Nicaraguan government and in July 1856 set himself up as the country's president.

Walker's regime was recognized as the legitimate government of Nicaragua by US President Franklin Pierce, and it initially enjoyed the support of some important sectors within Nicaraguan society. As ruler of Nicaragua, Walker relegalized slavery, with the goal of creating a new society of dominant White people and subordinate Black and Indigenous laborers. However, he never succeeded in implementing slavery.