Also note that all the slave owners were Democrats and the GOP was created to destroy slavery.
Which is why the Demos are trying so very, very hard to go back.
Some Whigs were slaveowners. The Republican Party at first was not calling for immediate abolition of slavery (people like Lincoln distanced themselves from the abolitionists and John Brown) but just to stop the spread to parts of the US which were not yet states, on the theory that that would eventually led to the end of slavery.