There have been other parties in the US. The Republican party, the party of Lincoln, rose from the ashes of two parties which died in the leadup to the Civil War, because they were unwilling to take up the cause of the abolitionists. The Republican party had no intention of taking up abolition. Neither did Lincoln. In the end, the war was handed to them anyway, started before Lincoln took office.
And no one was dumb enough to fight that war and _not_ end slavery. I mean, duh.
I feel like there's an analogy here somewhere. I'm not sure what it is. But I feel like there are some relevant lessons to be learned.
ETA: And it's fun watching someone at US News distance from a whack job at the Atlantic Monthly, and someone writing in a Salt Lake City paper explain how different Utah is from Kansas.