“If Lincoln fought the war to “free the slaves” then who went to war to “keep the slaves”?”
You have been trained well, little grasshopper. To that let’s add cogent and connected ideas.
The Confederate president fought to protect and defend his nation’s constitution and, arguably, President Lincoln did the same thing.
Both constitutions enshrined slavery.
But in one of those Constitutions it was legal for a state to end slavery. By 1860 15 states had done so. In the other Constitution, states did not have that right.