In 1862, Napoleon III sent an expeditionary force to occupy Mexico with the aim of establishing a Latin and Catholic empire in the region as part of his “Grand Design” for the Americas. The American Civil War served Napoleon’s purposes in many ways. First, the division of the Union neutralized the U.S. by rendering it unable to enforce the Monroe Doctrine. Second, the location of the new Confederacy, interposed between the Lincoln government and the Rio Grande, would protect Mexican interests. Third, faced with this interference in Mexican affairs, the insurgents showed their support for Napoleon’s enterprise.
From the very start of the war, the Confederates and their sympathizers tried to cast themselves out as the natural allies of Napoleon’s new Mexican regime, but the French had their doubts about the sincerity of the South’s support. Until the eve of secession, Southern nationalism was reflected by an unremitting desire for conquest in the Caribbean, Mexico, or Central America. To the Quai d’Orsay, a Confederate victory would signal the resumption of Southern conquests to fuel a slave empire. At the same time, Maximilian, the new emperor of Mexico set up by Napoleon, preferred to remain neutral and keep his distance from the Confederacy.