The northern states fought against having enslaved people counted as full citizens for various reasons, including moral and ethical objections to the institution of slavery. They believed that enslaved individuals were human beings and should be treated as such, rather than being legally classified as property or less than full citizens. Additionally, some northern states may have been concerned about the political implications of counting enslaved individuals as full citizens, particularly in terms of representation and voting rights. Ultimately, the northern states' opposition to counting enslaved people as full citizens reflected a broader rejection of the institution of slavery and a commitment to equality and human rights.
