It was the Democratic Party that fought to continue slavery which led to our Civil War. This was the deadliest conflict in American history, killing 624.511 men from both sides. All this was because the Southern States which, controlled by Democrats, wanted slaves to work on their plantations for free.
The Northern States, controlled by Republicans were abolitionist and saw the evil in slavery and wanted to end this inhumane practice. Many Christians formed a secret organization, “The Under Ground Railroad” to help men, women and children escape slavery to freedom. Slaves were hidden in homes as they traveled north to Free States. Later President Lincoln, a Republican, freed the slaves through his Emancipation Proclamation which eventually led to the freedom of all African American slaves.