Also, The Civil War was about the rights of states to own slaves, not "States' rights".
There's been a lot of revisionist history recently about how slavery was a "side issue" in the Civil War, and the real cause was states' rights. So using DuckDuckGo, I found a page titled, "The Declaration of Causes of Seceding States" on the Civil War Trust's website. On it is the text of the documents from Georgia, Mississippi, South Carolina, Texas, and Virginia explaining why they were seceding from the Union.
So what did they say? Let's start with Texas (Sorry, link doesn't take you to Texas, you'll have to scroll down to Texas). First, in explaining history of being accepted to Union:
(Texas) was received as a commonwealth holding, maintaining and protecting the institution known as negro slavery-- the servitude of the African to the white race within her limits-- a relation that had existed from the first settlement of her wilderness by the white race, and which her people intended should exist in all future time
And Texas's grievances? Does this sound familiar?
The Federal Government, while but partially under the control of these our unnatural and sectional enemies, has for years almost entirely failed to protect the lives and property of the people of Texas against the Indian savages on our border, and more recently against the murderous forays of banditti from the neighboring territory of Mexico;
Donald Trump must be surprised they didn't call them rapists. But back to grievances:
We hold as undeniable truths that the governments of the various States, and of the confederacy itself, were established exclusively by the white race, for themselves and their posterity; that the African race had no agency in their establishment; that they were rightfully held and regarded as an inferior and dependent race, and in that condition only could their existence in this country be rendered beneficial or tolerable.
Adopted in Convention on the 2nd day of Feby, in the year of our Lord one thousand eight hundred and sixty-one and of the independence of Texas the twenty-fifth.
Sounds like slavery wasn't a side issue for Texas. How about
Georgia? From the first paragraph:
For the last ten years we have had numerous and serious causes of complaint against our non-slave-holding confederate States with reference to the subject of African slavery. They have endeavored to weaken our security, to disturb our domestic peace and tranquility, and persistently refused to comply with their express constitutional obligations to us in reference to that property, and by the use of their power in the Federal Government have striven to deprive us of an equal enjoyment of the common Territories of the Republic.
Slavery didn't seem to be a side issue for Georgia either. What about
Mississippi?
Our position is thoroughly identified with the institution of slavery-- the greatest material interest of the world. Its labor supplies the product which constitutes by far the largest and most important portions of commerce of the earth. These products are peculiar to the climate verging on the tropical regions, and by an imperious law of nature, none but the black race can bear exposure to the tropical sun. These products have become necessities of the world, and a blow at slavery is a blow at commerce and civilization. That blow has been long aimed at the institution, and was at the point of reaching its consummation. There was no choice left us but submission to the mandates of abolition, or a dissolution of the Union, whose principles had been subverted to work out our ruin. That we do not overstate the dangers to our institution, a reference to a few facts will sufficiently prove.
Pretty clear it's about slavery for Mississippi. How about
South Carolina?
The Constitution of the United States, in its fourth Article, provides as follows: "No person held to service or labor in one State, under the laws thereof, escaping into another, shall, in consequence of any law or regulation therein, be discharged from such service or labor, but shall be delivered up, on claim of the party to whom such service or labor may be due."
This stipulation was so material to the compact, that without it that compact would not have been made. The greater number of the contracting parties held slaves, and they had previously evinced their estimate of the value of such a stipulation by making it a condition in the Ordinance for the government of the territory ceded by Virginia, which now composes the States north of the Ohio River.
The same article of the Constitution stipulates also for rendition by the several States of fugitives from justice from the other States.
The General Government, as the common agent, passed laws to carry into effect these stipulations of the States. For many years these laws were executed. But an increasing hostility on the part of the non-slaveholding States to the institution of slavery, has led to a disregard of their obligations, and the laws of the General Government have ceased to effect the objects of the Constitution. The States of Maine, New Hampshire, Vermont, Massachusetts, Connecticut, Rhode Island, New York, Pennsylvania, Illinois, Indiana, Michigan, Wisconsin and Iowa, have enacted laws which either nullify the Acts of Congress or render useless any attempt to execute them.
In short, northern states aren't returning escaped slaves. Finally,
Virginia. From the first paragraph:
The people of Virginia, in their ratification of the Constitution of the United States of America, adopted by them in Convention on the twenty-fifth day of June, in the year of our Lord one thousand seven hundred and eighty-eight, having declared that the powers granted under the said Constitution were derived from the people of the United States, and might be resumed whensoever the same should be perverted to their injury and oppression; and the Federal Government, having perverted said powers, not only to the injury of the people of Virginia, but to the oppression of the Southern Slaveholding States.
People can claim all they want that the Civil War wasn't about slavery but instead about states rights, but clearly it was about the states rights to own slaves.