Slavery in the United States = 1776 - 1865
89 years, not 400 years
The Republican Party was formed in 1854. It came to power in 1860 when it won Congress and the POTUS. Nearly all slaves were emancipated by the Republicans in 1863. All slaves were emancipated by the Republicans in 1865.
3 years of slavery under Republican rule, not 400 years.
Before 1776, it was British slavery.
After 1865 was the Democrat Party treating blacks as a separate society, often denying them basic rights as citizens. A little after 1865, the KKK was formed by Democrats, killing and terrorizing blacks for over a hundred years.
Excellent summation of the history of American slavery. I would also add that the founders outlawed slavery in the northwest territories in 1787. Then created a constitution that allowed states to outlaw slavery. As far as I can tell from my research we were one of the first countries to outlaw slavery in any part of our nation.