Always admired Frederick Douglass and have no doubt that's how he felt. Slavery was an evil institution. But there's more to the story than slavery. The North wasn't fighting to end slavery. History says they were fighting to preserve the Union. But in doing so they were basically saying the states were not free and were subject to the federal government. JMO, but from everything I've read, that was not the intentions of the FFs. But for Douglass, who was born a slave, I completely understand why he felt the way he did. He had experienced that evil institution first hand. But I also think that narrowed his focus to where he did not see the entire significance of what the Civil War was about. It wasn't just about one thing. But making it about one thing makes it easier to villainize the South. And as they say, history is written by the victors.
As I noted a couple of days ago, it is impossible to know all the reasons why Southerners seceded. The Deep South states, who were more heavily invested in cash crops at the time - cotton, tobacco, rice, and sugar cane - were therefore more heavily invested in slavery, and slavery had also become a part of the culture of the Deep South.
For the Upper South states, the reasons for secession are different. They were much less invested in cash crops, and thus less reliant on slavery Not to imply those weren't slave states, they were, just not as invested as in the Deep South. And those Upper South states, because of geography were more heavily invested in trade with the northern states than the Deep South.
Same is true with the North. We just can't say 'the North' as a whole was thinking this or that. If you look at the Republican Party in 1860, a party that was less than a decade old, it had risen out of the ashes of the WHIG Party, which had collapsed following the Mexican-American War. But the new Republican Party also gained membership from former members of the Free-Soil Party, the Liberty Party, and the American (or Know-Nothing) Party. The WHIGs had basically been an anti-Andrew Jackson/Democratic Party, as WHIGs favored protective tariffs, federal funding for infrastructure projects, and a national bank. Lincoln was a life-long WHIG until the party's collapse in the early 1850s. The Free-Soil Party's goals were to keep slavery out of the western territories as those territories applied for statehood, but there were differences within that party, as some members wanted to keep slavery out of the territories, while others in the party wanted to keep blacks out of the territories, free or slave. Then you had the members of the small Liberty Party, who were the abolitionists. Not only did they support free-soil in the territories, they wanted slavery ended period, although some wanted it done immediately while others called for a graduated process.
Lastly, you still had a Democratic Party in the north, led by Sen. Stephen Douglas of Illinois (he of the famous Lincoln-Douglas debates of 1856). The northern Democratic Party generally supported the southern wing of the party, although those that didn't joined the new Republican Party. Mainly the northern wing supported slavery from an economic standpoint. But Douglas angered the southern wing during the 1860 primaries when he would not support the southern wing's insistence on a platform demanding a constitutional protection for slavery in the territories. Douglas preferred that territories applying for statehood make their own choices. This is what split the party during the general election, as the southern wing put up its own presidential candidate to run against Douglas, allowing Lincoln to win with virtually zero support outside the North.
But back to the North, while Lincoln was a WHIG until the day he joined the Republican Party, he also agreed with the principles of the Free-Soil Party, that slavery could not be allowed into the territories. He believed this because he believed that slavery was destructive to free labor principles. He was not against free blacks in the territories as some in the party were; his beliefs were based on his WHIG principles; he believed in the growth of the new industrial sector and the free labor that was needed for it. But he was also a strong constitutionalist, and so believed that slavery where it existed in the South was constitutionally protected.
Northerners also disagreed on whether the South's actions were a secession or rebellion. Lincoln firmly believed that it was a rebellion. When the war was over (and Lincoln was dead and his Democrat VP was now president) the Republican-controlled Congress treated it as secession, and I think this was mainly because if it as considered secession that meant the seceding states would have to apply to rejoin the Union. This meant they had to go through the territorial process, which was constitutionally controlled by Congress, giving Congress the power to appoint military governers to the former secession states.
At any rate, long story short, the main Republican platform in 1860 was that slavery would not be allowed into the territories. Many, if not most, in the party believed that this would cause the slow strangulation of slavery where it existed, something pro-slavers in the South also feared, hence their secession following his election.
