My read of History says that the American Civil War is fought, basically, over Slavery, despite arguments of some about "States' Rights."
The passage of the 13th, 14th, and 15th Amendments to the US Constitution are attempts to correct for Slavery, as was the Civil RIghts Act of 1964, which dealt with the effects of Jim Crow laws in the former Confederacy.
While supporters of the Confederacy may not have the Moral High Ground, those who fought to abolish slavery maintain a semblance to ownership of some of that Moral High Ground. That effort to abolish slavery was the reason for the beginning of the Republican Political Party in the US.
AI Summary
To understand the start of the Republican Party, consider these key reasons:
Opposition to the expansion of slavery into new territories and states.
Response to the perceived failures of the existing political parties, particularly the Whigs and Democrats.
Advocacy for free soil and free labor principles, promoting economic opportunity for all.
Formation in 1854 as a coalition of former Whigs, Free Soilers, and anti-slavery Democrats.
Emergence as a political force to unite various factions against the pro-slavery agenda.
Aimed to uphold the Union and prevent the secession of Southern states.
and
The Republican Party, also known as the Grand Old Party (GOP), is one of the two major political parties in the United States. Founded in 1854, it is the second-oldest extant political party in the United States after its main political rival, the Democratic Party.
The Republican Party emerged to combat the expansion of slavery into western territories after the passing of the Kansas–Nebraska Act. The early Republican Party consisted of northern Protestants, factory workers, professionals, businessmen, prosperous farmers, and after the Civil War also of black former slaves.
https://en.wikipedia.org/wiki/History_o ... ed_States)