Like several of his predecessors, Franklin Pierce found foreign policy a welcome change from the domestic conflicts over slavery. Unfortunately, his lack of leadership and his tendency to give in to pressure groups hampered his effectiveness in the foreign arena.

Even though the Mexican War had ended, there were border disputes that had to be settled. Land that now comprises lower Arizona and New Mexico was part of a proposed southern route for a transcontinental railroad. Pierce was convinced by Secretary of War Jefferson Davis to send Senator James Gadsden (who had personal interests in the rail route) to negotiate the Gadsden Purchase with Mexico. Under the agreement, the U.S. paid Mexico $15 million to secure the land. The Treaty included a provision allowing the U.S. to build a transoceanic canal across the Isthmus of Tehuantepec, but this option was never exercised. The acquisition of land in this purchase secured the final boundaries of the continental United States.

Attempt to Acquire Cuba

Far less successful was Pierce's pet cause—the annexation of Cuba. For years, Southerners had coveted the great island as a place to expand their slavery-driven agricultural economy. Failed filibustering expeditions during the Taylor and Fillmore presidencies were evidence of the South's attempts to obtain this slaveholding Caribbean possession of Spain.

Southern interests in Cuba were understandable. After all, that nation allowed slavery and was developing a plantation form of agriculture, and would continue to do so until two decades after the Civil War.

During Pierce's administration, many Americans reasoned that if Cuba were to be purchased from Spain, they would in effect have another slave state. The wrong man was charged with the delicate task of negotiating with Spain's poor but proud king. Pierre Soulé, an overbearing Southerner, had been named Pierce's minister to Spain, with instructions to go as high as $130 million, but Soulé had little patience for the slow ways of the Spanish court. The more he tried to bully Spain into selling Cuba, the more that nation resisted the idea. Soulé even rewrote the treaty to include threats of American military action if Spain did not comply, which only stiffened Spanish resolve. Soulé met with James Buchanan, Pierce's ambassador to England and future President of the United States, and John Mason, the minister to France. Together, they drafted the Ostend Manifesto, a document that set the justifications for American possession. The Manifesto also warned that if Cuba refused America's proposal, "internal peace" in the United States might be threatened by continued Spanish control, since slaves might revolt on the island, threatening the institution of slavery in the U.S. Under such circumstances, America might be required to take control of Cuba. After the document was published, Pierce's secretary of state, William Marcy, was forced to repudiate the Manifesto because of the diplomatic uproar in Europe and in the north that ensued.

England, Central America, and Asia Pacific

While a tariff agreement with Great Britain was reached, Pierce expelled the British ambassador to the U.S. for his recruitment of former British immigrants as soldiers to fight in the Crimean War against Russia. Additionally, the President opposed British settlement in Central America, and he supported American military action to keep that imperialist nation out of a region considered by Americans to be under their control.

In 1856, Pierce recognized a dictatorship in Nicaragua established by William Walker, an American freebooter who had conquered that nation and had begun to introduce slavery. Walker hoped to gain Nicaragua's entry into the Union as a slave state. Walker's control soon angered railroad titan Cornelius Vanderbilt, who intended to build rail lines and a canal in that nation. Vanderbilt pressured Pierce to use the U.S. Navy to force Walker to "surrender" the country. Walker then took his forces to Honduras, where the British navy captured him. He was executed by a Honduran firing squad.

President Millard Fillmore had commissioned Commodore Matthew Perry's exploratory mission to Japan, a nation that had been closed to Europeans for centuries. Jane Pierce, meanwhile, was slowly wasting away from tuberculosis, and Franklin traveled with her to the West Indies in hopes that the warmer climate would benefit her. It did not, and she died in late 1863.