[3] There were similar ambitions towards states of northern Mexico such as Tamaulipas, where it was believed the climate would suit the introduction of slaves, but Cuba had the advantage of an existing plantation economy.
The campaign to end Spanish rule in Cuba attracted support from a number of southern political figures who were later prominent Confederates including Jefferson Davis.
They received strong backing from Mississippi Governor John Quitman, who formed an alliance with the Venezuelan-born adventurer Narciso López.
An expected uprising by Cuban revolutionaries did not occur and the filibusters rapidly fled back to Florida pursued by the Spanish Navy.
[7] Lopez, Quitman and others were prosecuted for violating the Neutrality Act but a jury in New Orleans, where they were wildly popular for their efforts, acquitted one of their conspirators and the remaining indictments were dropped.
By the time the expedition landed at Pinar del Río Province in western Cuba, the Spanish Army had already defeated the uprisings which had been more limited than American newspapers reported.
[11] Well-prepared for López this time the Spanish troops under José Gutiérrez de la Concha, Captain General of Cuba, defeated the filibusters in several engagements killing around two hundred and taking the rest prisoner.
[14] Despite the inflamed public mood in the south, the administration of Millard Fillmore was embarrassed by the failure to prevent the expedition from sailing in the first place and confined itself to securing the release of remaining American prisoners still in Spanish hands.
Although this was called off under diplomatic pressure, and opposition by Northern free soilers, attempts to purchase Cuba continued until the Civil War broke out.