Another potential PoD:
In 1805 the Governor of the Indiana Territory William Henry Harrison attempted to push through legislation to legalise slavery in the territory. Legalising slavery in the Northwest Ordinance had been a project of his for a while as he thought it would encourage settlement and make the territories more economically viable. Earlier that year he, along with the Indiana Territory Representative Benjamin Parke, had lobbied Congress to temporarily suspect article 6 of the Northwest Ordinance which prohibited slavery as well as give the territories the right to choose whether or not to legalise slavery (I have seen conflicting accounts of whether they were successful). When Congress granted the Indiana Territory its own elected legislature in 1805 there was only a single anti-slavery candidate elected. Harrison's proposed Bill to legalise slavery was blocked by the representatives due to a disagreement over establishing a separate Illinois territory which Harrison was staunchly opposed to (although would eventually happen when those representatives lobbied Congress directly). Now lets say that during this time the legislation passes, either due to the representatives dropping their demand for a separate territory or Harrison deciding to support them, and as a result slavery is legalised in what was basically the western half of the Northwest Ordinance. Because of this there's much more southern migration into this/these territories and as a result Indiana and Illinois have a chance to be incorporated as Slave States or revert to Slave States down the line (as Illinois attempted to do I believe).
In 1805 the Governor of the Indiana Territory William Henry Harrison attempted to push through legislation to legalise slavery in the territory. Legalising slavery in the Northwest Ordinance had been a project of his for a while as he thought it would encourage settlement and make the territories more economically viable. Earlier that year he, along with the Indiana Territory Representative Benjamin Parke, had lobbied Congress to temporarily suspect article 6 of the Northwest Ordinance which prohibited slavery as well as give the territories the right to choose whether or not to legalise slavery (I have seen conflicting accounts of whether they were successful). When Congress granted the Indiana Territory its own elected legislature in 1805 there was only a single anti-slavery candidate elected. Harrison's proposed Bill to legalise slavery was blocked by the representatives due to a disagreement over establishing a separate Illinois territory which Harrison was staunchly opposed to (although would eventually happen when those representatives lobbied Congress directly). Now lets say that during this time the legislation passes, either due to the representatives dropping their demand for a separate territory or Harrison deciding to support them, and as a result slavery is legalised in what was basically the western half of the Northwest Ordinance. Because of this there's much more southern migration into this/these territories and as a result Indiana and Illinois have a chance to be incorporated as Slave States or revert to Slave States down the line (as Illinois attempted to do I believe).