My favorite way of pointing out the nuances of the Civil War it to note that for each side, the primary issue was the opposite of what the latter-day partisans of the two sides say it was. For the South the issue was slavery, and the Confederacy was formed to defend that institution. For the North the issue was states rights, the Union going to war to vindicate the position that states do no have the right to secede uniliaterally.
If the North was going to war to invalidate the idea of a State's Right to secede from the compact, alone or in groups, then State's Rights was certainly an issue.
As I have noted, if the founding governments of their respective several and sovereign States had believed for a moment that in the event their State was no longer served by the compact that they could not leave that compact, it never would have been ratified in the first place. After all,
Why was slavery an issue if only 1/4 of southerners held slaves?
First, the slaves were the tractors before the industrial age. Certainly, draft animals did the heavy work, but farming was (and to some extent still is) labor intensive. Today, machinery acts as a force multiplier, but the job is still 24/7/365 to be done right. Prior to the introduction of many of the antecedents to today's planting and harvesting machinery, planting, cultivation, harvesting were done by hand. Crops like tobacco still rely on human labor for harvesting and lest we forget, that presently demonized crop was such an essential cash crop, it was literally used as money, including for the payment of taxes. The summary elimination of the agricultural labor force upon which the South relied for the production of the very stock in trade: agricultural products would have been economically devastating. The North had different needs, and a steady influx of immigrants the South did not, enough so that it could pick and choose which European groups were treated poorly. You could starve to death as an immigrant in the North, as a slave you'd at least be fed (or the owner would lose their investment).
Speaking of that investment, the summary and total manumission the Northerners (or at least the most ardent abolitionists) sought made no provisions for compensating owners for what at the time was considered "property", to be removed from them without due process, for no crime unless a new (
ex post facto) law was passed.
Consider:
By the mid 19th Century, exports of raw cotton accounted for more than half of US oversees shipments. What wasn't sold abroad was sent to mills in northern states including Massachusetts and Rhode Island to be turned into fabric.
The money southern plantation owners earned couldn't be kept under mattresses or behind loose floorboards.
American banks accepted their deposits and counted enslaved people as assets when assessing a person's wealth.
In recent years, US banks have made public apologies for the role they played in slavery.
In 2005, JP Morgan Chase, currently the biggest bank in the US, admitted that two of its subsidiaries - Citizens' Bank and Canal Bank in Louisiana - accepted enslaved people as collateral for loans. If plantation owners defaulted on loan payment the banks took ownership of these slaves.
JP Morgan was not alone. The predecessors that made up Citibank, Bank of America and Wells Fargo are among a list of well-known US financial firms that benefited from the slave trade.
"Slavery was an overwhelmingly important fact of the American economy," explains Sven Beckert, Laird Bell Professor of American History at Harvard University.
sourceEven northern interests were involved, first in the trade, but later as counting the value of slaves held as collateral for loans, loans which were deeply involved in maintaining the production of agricultural products on which the North not only relied for trade with Europe, but for its own textile and other mills.
The economic issues were not as simple as might appear, seriously wealthy interests were involved, both from the banking and industrial standpoint,and the simple bottom line is that the mercantile and banking class could not afford to have the South trading its products with the world, rather than being heavily tied to the Northern interests. Those loans were the leverage to keep the trade on track. The threat of summarily dismissing collateral for those loans would have left notes being called in and financial ruin/confiscation of major assets.
While, for instance, manumission was gaining in popularity in States like Maryland, where the expansion of the Federal District, Annapolis, and Baltimore (a major port and trade hub) changed the crops planted in the area to produce for market, requiring fewer slaves, and leading to many being freed, the need in the deeper South was still for agricultural labor to produce the crops to service the loans often held by northern banks.
Practical cotton harvesting machinery wasn't invented until the 1920s, and tobacco is still harvested by hand.
By 1860, though, just under half of the blacks living in Maryland were free, and manumission had been steadily increasing since 1810
source When the South threatened to leave (the first mutterings were as early as the 1830s) not only were the collateral holdings of the northern banks threatened, but the lock on southern materials for the markup in trade and the raw materials to feed the mills was as well. Secession was the economic (and political) reply to the brickbat of emancipation which the north had waved once too often, but the underpinnings of the issue ultimately were economic, and that economic issue boiled down to two matters: The Right of a State to make its own laws, and at its core, the relation of that to slavery.
Considering the movement was away from slavery for economic reasons, namely that the influx of immigrants, often unwelcome in urban areas except to keep a sufficient surplus of labor to keep wages low, trickled down into the South. As that labor became more available, we see things like forbidding slaves from the holds of ships being loaded, not to prevent escape so much as to protect the investment. If the cargo shifted, the slave would likely be severely injured or killed, a loss of an asset. Instead, if a hireling was sent into the hold and was killed or injured, a modest stipend might be tendered to the widow and hire another. In addition, as I have mentioned in other posts, the slave had to be provided for: food, housing, adequate clothing and medical care (such as it was), or the return on investment would be low or nonexistent. A wage earner, on the other hand, would provide such themselves out of their pay, or if housed (room and board), that could be deducted from their wages. The "Company Store" got so bad that many equated it with slavery, and no initial investment was necessary. Not all were treated thus, but it was common enough, and a system which persisted into the 20th century, in coal mining towns, especially.
If left to its economic devices, restrained to the States which practiced it, it is likely slavery would have died a natural death out of economic considerations.
The war was fought, invading the South, to preserve the Union, at least in the minds of many Northerners who made up the Army. Allegedly, Maryland was invaded for the purpose of securing the Federal District, (in actuality, with the occupation of the State Capitol, to prevent a vote on secession). There was no great cry of going forth to free people held in bondage, but to quash rebellion, in their eyes. It was no coincidence that after the emancipation proclamation there were problems in the ranks over not fighting to free slaves, and draft riots in New York City in mid 1863. Emancipation alone simply was not
casus belli in the minds of Northerners, but the preservation of jobs and their economy was.
My point, however, is simply this. Slavery, as an issue, cannot be separated from the States' Rights issue, as it was the State's Rights issue which determined whether slavery would be allowed to persist. The roots of the war, of the forceful and brutal conquest of the South to make it stay in a 'voluntary' Union were by and large (as in all wars) economic.