You’re being disingenuous, as usual. The war began when the eleven southern states seceded and formed the Confederacy. Their reason for doing so was the preservation of slavery. The Southerners said so at the time. Specifically the election of Abraham Lincoln was declared intolerable even before the election. Hostilities began with the firing on Fort Sumter.
The North, in 1861, fought to preserve the Union. By the end of the war the abolition of slavery had been added as an ultimate goal. But the Confederacy started the war. The reason was slavery.
Actually it didn't. Initially it was only 7 states that seceded, and there was no war. The other states didn't join it until after Lincoln had triggered the war and announced the raising of troops to subjugate the 7 states that had seceded.
But addressing your point more directly, why would secession provoke a war? Does not the US Declaration of Independence declare it is a God given right for states to have independence if they want it?
If it declared it a right in our separation from England, why wouldn't the child nation of that document respect that same right for others?
Their reason for doing so was the preservation of slavery.
Well, so the people who went to war against them have been claiming ever since, but that assertion does not stand up to the facts. The US was going to preserve slavery indefinitely, because there were simply not enough states who would vote to change that, so slavery would have been preserved in the USA. Add to that the fact that Lincoln and his Republican allies in Congress passed the Corwin amendment, and that makes it even more certain that slavery would always be preserved in the USA for the indefinite future.
So the claim that they went to war to preserve something that was never threatened, and was indeed signed away at the very beginning of the conflict, is simply a deliberate lie meant to justify all the bloodshed, carnage and trampling of our constitutional government.
Hostilities began with the firing on Fort Sumter.
Hostilities began when Anderson, in the middle of the night, ordered his men to spike and burn all the cannons in fort Moultrie, kidnap a ship's captain by force, and compel him to carry his men to unoccupied and under construction Fort Sumter, and then expel all the workmen working there, with the town waking up the next morning having cannons under a hostile force threatening them.
Anderson's seizure of Fort Sumter was the first hostile act of the war.
The North, in 1861, fought to preserve the Union.
They didn't have a right to force people to remain part of their corrupt system. The idea that you could force others to serve you is the same foundation on which slavery is built.
By the end of the war the abolition of slavery had been added as an ultimate goal.
This is about the closest thing you've said to being accurate so far, but still not quite accurate. Clearly they did not march any armies into the Union slave states to abolish their slavery. So no, it wasn't the ultimate goal of the war. The ultimate goal of the war was to force subjugation on states that had dared defy the corruptocracy running Washington DC for the betterment of the Northeastern elites who are still running it today.