Answer:
There were several factors that led to the establishment of the American Colonization Society. The number of free people of color grew steadily following the American Revolutionary War, from 60,000 in 1790 to 300,000 by 1830.[1]:260 Consequently, slaveowners grew increasingly concerned free blacks may encourage or help their slaves to escape or rebel. In addition, many White Americans saw African Americans as racially inferior and felt that "amalgamation," or integration, of African Americans with “mainstream American culture” was impossible. This reinforced the notion that African Americans should be relocated to somewhere they could live free of White prejudices.
The African-American community was overwhelmingly opposed to the project; in most cases, their families had lived in the United States for generations, and their prevailing sentiment was that they were no more African than white Americans were European. Contrary to stated claims that emigration was voluntary, many African Americans, both free and enslaved, were pressured into emigrating. Indeed, slaves were sometimes manumitted on condition that they leave the country immediately.[2]
According to historian Marc Leepson, "Colonization proved to be a giant failure, doing nothing to stem the forces that brought the nation to Civil War."[3] Between 1821 and 1847, only a few thousand African-Americans, out of the then millions in the US, emigrated to what would become Liberia. Many of them died from tropical diseases. In addition, the transportation of the emigrants to the African continent, including the provisioning of requisite tools and supplies, proved very expensive.[citation needed]
Starting in the 1830s, the Society was met with great hostility from white abolitionists, led by Gerrit Smith, who had supported the Society financially, and Wm. Lloyd Garrison, author of Thoughts on African Colonization (1832), in which he proclaimed the Society a fraud. According to Garrison and his many followers, the Society was not a solution to the problem of American slavery—it actually was helping, and was intended to help, to preserve it.[4]