Final answer:
The contradiction between fighting for liberty while upholding slavery led many Northern colonists to advocate for emancipation during and after the American Revolution, resulting in eventual bans and gradual emancipation in Northern states.
Step-by-step explanation:
The American Revolution stoked debates about the values of liberty and freedom, leading many, particularly in the North, to grapple with the inconsistency of pursuing independence while allowing slavery. Religious groups like the Quakers in Pennsylvania and New Jersey, along with leaders such as James Otis and Arthur Lee, criticized slavery for contradicting the fundamental beliefs their new nation was supposed to represent. States in the North, including Pennsylvania and Vermont, responded by either outright banning slavery in their state constitutions or taking significant legal action against it, which led to policies of gradual emancipation. Despite the efforts to address slavery, the issue would continue to cause division, eventually becoming a predominantly southern phenomenon after the nation failed to abolish it outright.