Update 2: Secession documents: https://www.abbevilleinstitute.org/the-truth-about-the-secession-documents/
Update: In 1861, the newly elected Republican Congress passed the Morrill Tariff Act (https://en.wikipedia.org/wiki/Morrill_Tariff) and they also introduced the Corwin Amendment to preserve slavery (https://en.wikipedia.org/wiki/Corwin_Amendment).
War in Armenia, Ukraine, and Israel. Fears over China and Iran. Now is a good time to reflect on a past war fought in the Americas over a century ago.
Statues cannot be racist as they are inanimate objects, yet primitive minds will grab and attack anything they fear, including destroying art. Right now, a statue of Robert E. Lee is being melted down (https://southernnation.org/featured/anti-southern-bigots-finally-got-their-wish/). Ayn Rand wrote of such mindsets in her book Return of the Primitive. Such minds believe in witchcraft and superstition.
Confederate monuments are attacked by Democrats and their progressive and Marxist allies. Well, if the monuments have to come down for being racist, the Democrat Party should be abolished for defending slavery. The Republican Party was founded by John C. Fremont, an abolitionist but in losing his presidential election in 1856, the Party had to expand their platform.
Tariffs entered the picture as did many ideas of Henry Clay. This is what would result in South Carolina leading the way in secession as it had before during the Nullification Crisis in about 1830 over tariffs. Of the 15 slave states, only 7 states seceded leaving, the majority of slave states and slaves remained in the Union.
But Lincoln had different plans and clearly stated so in his First Inaugural Address. He wanted to defend the Federal government’s ability to tax and had no intention in interfering with slavery.
Many say the South was defending “states’ rights” but this is misleading. Here is the dirty secret. The Republican Party explicitly defended States’ rights as well and said so in their platform.
So when Fort Sumter came under attack President Lincoln called up the militia to invade the South. General Robert E. Lee, being from Virginia, did the only principal thing he could do: resign. Virginia, North Carolina, Arkansas, and Tennessee seceded from the Union next, but not over slavery, but over the violation of the Republican Party’s platform claims of States' rights. The Confederacy fought a defensive war.
Also, General Lee is the only American general to single-handedly end a war when he surrendered his troops to Union General Grant. In comparison, Union General Sherman was a war criminal who burned down civilian homes and destroyed livestock and crops, impoverishing the South and leaving it destitute. This is why Lee matters. There are far more statues of Lee compared to Sherman.
Many Nebraskans frown on the Confederate flag, but the Confederate flag is the flag of peace, of self-defense, and self-determination. But the flag is in the past now but many peoples in the world dream of self-determination and will view the history of the Confederacy favorably, and particularly Robert E. Lee.
Resources:
Lincoln’s Address: https://www.gilderlehrman.org/sites/default/files/inline-pdfs/01264_0.pdf
Republican Platform of 1860: https://upload.wikimedia.org/wikipedia/commons/7/7e/National_republican_platform._Adopted_by_the_National_Republican_Convention%2C_held_in_Chicago%2C_May_17%2C_1860.jpg
Take a look at South Carolina's secession document. It is explicit about the reason for their secession.
The problem wasn't that there weren't plenty of excuses other than slavery for the rift between Northern and Southern states.
The problem was that if the U.S. added any more free states to the Union, the slave states would lose the voting majority that had allowed them up to that point to keep their slaves. They knew that public opinion was against them and that it was growing ever more firmly abolitionist.
This was true even in the South. Most people didn't own slaves. Even in South Carolina, where plantations were the backbone of the economy, the number of American citizens owning slaves rose to barely half the total of those eligible to vote, and in most slave states, the percentage of American citizens who owned slaves was quite a lot less.
When Abraham Lincoln won the race for president, it became clear that the next few states to be admitted to the Union would be free states. This is why he didn't have to come out and openly support slavery: it was already being done in by sheer force of public opinion.
So--yes--the Civil War was about State's Rights and it was also about slavery--because it had everything to do with whether the slave states would be permitted to keep their slaves.
The plantation economic model was unworkable without slave labor.
In the North, the abolitionists had instead built factories powered by coal and steam, and by water and other mechanical ingenuities of the time. While factory conditions were far from ideal, there was a big push to find ways to make the jobs safer and to provide a living wage as well as mental stimulation for their workers by employing people to read aloud to them while they completed their repetitive tasks.
Meanwhile, Southern plantation farmers had no way at that time of replacing manual labor in the cotton fields with mechanical marvels, so they either had to go to war or quit farming cotton and tobacco. And they weren't about to quit farming these crops--at least not then. They were too lucrative.