Meanwhile, the doctrine of manifest destiny had become increasingly sectionalized as the decade progressed. While there were still Northerners who believed the United States should dominate the continent, most were opposed to Cuba's annexation, particularly as a slave state. Southern-backed filibusters, including Narciso López, had failed repeatedly since 1849 to 1851 to overthrow the colonial government despite considerable support among the Cuban people for independence, and a series of reforms on the island made Southerners apprehensive that slavery would be abolished. They believed that Cuba would be "Africanized," as the majority of the population were slaves, and they had seen the Republic of Haiti established by former slaves. The notion of a pro-slavery invasion by the U.S. was rejected in light of the controversy over the Kansas–Nebraska Act. During internal discussions, supporters of gaining Cuba decided that a purchase or intervention in the name of national security was the most acceptable method of acquisition.