Wrong again. The GOP was taking a MORAL POSITION against slavery. Hundreds and thousands of laws are based upon a moral position, i.e, a determination of what is believed to be the correct, right thing to do.
The GOP took a moral stance on a political issue.
Not all moral issues have anything to do with politics.
That is why we don't punish people for adultery or fornication, although many self-righteous prigs would love to do so.