That is an overstatement. The Republicans wanted to stop the expansion of slavery into the territories and limit the expansion of the slave plantation system. The Republicans were not abolitionist before the Civil War.
The early Republican slogan was: "Free soil, Free labor, Free men," indicating opposition to slavery and the plantation system.
Thanks for the feedback.
I suppose I could change it to something like this:
The Republican Party was founded primarily to oppose the expansion of slavery, and it eventually abolished slavery. The Democratic Party fought them fiercely and tried to maintain and expand slavery.
What do you think about that?
Also, what did you think about the historical accuracy of the rest of the article?