The Ostend Manifesto is a document written in 1854. This document describes the reasons that the United States can use to buy Cuba from Spain, and the content also implies that the United States should declare war if Spain refuses. For a long time the expansionist slave owners wanted the United States to annex Cuba. At the national level, American leaders are actually satisfied that the island of Cuba remains in the hands of weak Spain and not in the hands of great powers such as Britain or France. The Ostend manifesto proposed a change of foreign policy by trying to justify the use of military force to seize Cuba for national security. This document is generated from debates related to slavery in the United States, Manifest Destiny, and Monroe's Doctrine, because slave owners want to have new territory to expand slavery.
During the administration of President Franklin Pierce, a pro-southern Democrat, Southern expansionists called for Cuba's takeover as a slave state, but the outbreak of violence due to the Kansas-Nebraska Act renders the government unaware of how to act. At the suggestion of Secretary of State William L. Marcy, United States ambassadors in Europe - Pierre Soulé in Spain, James Buchanan in Great Britain, and John Y. Masondi of France - met to discuss strategies related to the Cuban takeover. They met secretly in the city of Ostend, Belgium, and formulated a written message to Aix-la-Chapelle. The document was sent to Washington in October 1854 and underlined why the purchase of Cuba would benefit both nations and stated that the United States was "justified in taking over" the island from Spain if Spain refused to sell. However, Soulé made no secret of this meeting, resulting in unwanted publicity in Europe and the United States. The United States government was finally forced to publish this written content, which resulted in irreparable harm.
The contents of this written news are published as requested by the House of Representatives. The document called "Ostend Manifesto" was immediately condemned by the northern states of the United States and European countries. The question of the Cuban takeover was not finally discussed until the end of the 19th century, when there was support for Cuban independence from Spain.