Why were most of the states against slavery?

Most states were against slavery due to a combination of moral, economic, and political factors. Many northern states embraced abolition as a moral imperative, influenced by Enlightenment ideals of human rights and equality. Additionally, the industrial economy in the North did not rely on slave labor, leading to a preference for free labor. Politically, opposition to slavery was tied to the growing sectional tensions between the North and South, as northern states sought to limit the expansion of slavery into new territories.