Pierce vetoed funding for internal improvements, called for a lower tariff, and vigorously enforced the Fugitive Slave Act of 1850. Influenced by the Young America expansionist movement, the Pierce administration completed the Gadsden land purchase from Mexico, clashed with the British Empire in Central America, and led a failed attempt to acquire Cuba from the Spanish Empire. Pierce's administration was severely criticized after several of his diplomats issued the Ostend Manifesto, which called for the annexation of Cuba, by force if necessary. His popularity in the Northern free states declined sharply after he supported the 1854 Kansas–Nebraska Act, which nullified the Missouri Compromise. Passage of the act led directly to a long and violent conflict over the expansion of slavery in the Western United States.