It was slavery all along

Slavery was the issue but in a different context.

The dispute was over whether or not to allow slavery in the new territories NOT over any abolishment of slavery in the states that already existed.

Pennsylvania law 1780-
That all Persons, as well Negroes, and Mulattos, as others, who shall be born within this State, from and after the Passing of this Act, shall not be deemed and considered as Servants for Life or Slaves; and that all Servitude for Life or Slavery of Children in Consequence of the Slavery of their Mothers, in the Case of all Children born within this State from and after the passing of this Act as aforesaid, shall be, and hereby is, utterly taken away, extinguished and for ever abolished.

Correct.

Several new england states passed similar laws in the late 1700s - early 1800s.

Yet there was no clamoring towards the southern states demanding they follow suit.

The conflict was over slavery being permitted in the new territories to the west.

LABOR FOR LONGTERM PROFIT in a nutshell. Choo-Choo Train is The Lost Cause

SLAVERY in the USA prior to the Civil War is African American Labor in the East, west to the Mississippi River

Chinese Labor at times was indentured servitude and was used in the Far West.

Irish immigrant Labor was near indentured servitude and was used everywhere in North America to take advantage of The Potato Famine in their homeland, and English/UK industrial revolution Problem.

Pre Civil War, during and just after The Mexican/American War, when the USA acquired California, the USA Secretary of War, Jefferson Davis, used the USA Army Corps of Engineers to survey and map out topographical practical routes for 5 additional transcontinental Railroads to connect with the North South East Coast Connector. Four would connect East West, One North South on the West Coast between San Diego and Seattle. Ports, and Land Transportation for the 3rd Industrial Revolution.

Jefferson Davis wanted to give priority to the Southern Connection to San Diego, using the Cheapest Labor available across the Southern USA. Slavery.

Abe Lincoln wanted to connect Chicago through St. Louis to San Francisco.... with Chinese Labor handling the Sierra Nevada, and Irish Labor handling St. Louis to Promontory Point, Utah...

Minnesota to Seattle connected later, surveyed by McClellan... as Southern connection once Reconstruction assured Republican Control and Railroad Magnate Uber Wealth Donors set to succeed for the next 80 years.

ALL Officers whether Union or Confederate wanted to get a piece of the RailRoad Pie to come. Slavery, yes it was ONLY about Slavery. Don't look at anything else but that Shiny Object. SLAVERY,
Slavery, slavery.............. did anyone mention slavery? That is the cause and solution that mandated the economic collapse of the South, so the North could get out of paying them for their loss of property value, as the UK did when 30 years prior, they abolished slavery in their country.

5th amendment seizure of property by the Federal Government is fairly spelled out in the U.S. Constitution. Why did the North and the Union Cause abdicate this responsibility, that the UK had no problem fairly paying?

The Economic Outcome Fallout of the Civil War is Control over Steel needed to manufacture Transcontinental Railroads, Track, Engines, & Cars 1869-1900. Slaves and the Civil War aren't the only things Jefferson Davis lost when Robert E. Lee surrendered at Appomattox Courthouse.