The Republican long game

Was to admit free western states and tip the balance of power to eventually get rid of slavery. The party was founded on the Slavery issue which tore the Whigs apart. Lincoln was a political realist and knew he needed to appeal to white people who only cared about slavery inasmuch as it threatened their economic prospects.

If we didn't have a civil war, the move to get rid of it in totality was probably 20 years away, but the Republicans wanted to eliminate the institution and the South knew it.