Earlier quoted context omitted.
Yes, this is main way that States Rights affected the Civil War: northern states ignoring federal law and federal court rulings about returning escaped slaves. I can see several folks in this very discussion who might be surprised by this bit of history. Edit: so far two different people think I am mischaracterizing what Southern states said at the time about their state's rights. I wasn't talking about that at all.…
This is also wrong. The Civil War was about slavery. There's a speech in which a defining characteristic of the confederacy is slavery. Keep playing revisionist history.
I believe the "Civil War was about states' rights" line began in the 19th century [1], around the same time as "the number of Confederate memorial installations peaking around 1910 — 50 years after the end of the Civil War and at the height of Jim Crow" [2].
In reality, "Confederate states did claim the right to secede, but no state claimed to be seceding for that right. In fact, Confederates opposed states’ rights — that is, the right of Northern states not to support slavery" in "Northern states [failing] to 'fulfill their constitutional obligations' by interfering with the return of fugitive slaves to bondage" [3].
[1] https://www.npr.org/sections/itsallpolitics/2011/04/12/13535...
[2] https://www.businessinsider.com/confederate-statues-meaning-...
[3] https://www.washingtonpost.com/outlook/five-myths-about-why-...