[DiogenesLamp]

Slavery in the North was a shadow of what existed in the South, pal.

Have you ever heard that joke in which the punchline is:

We've already determined what kind of girl you are, now we are just haggling over the price.

You can't don the moral armor of fighting against the South because of "slavery" when you continue to practice it yourself. It clearly wasn't "slavery" that was causing the invasion and fighting.

[BroJoeK]

DiogenesLamp: "You can't don the moral armor of fighting against the South because of "slavery" when you continue to practice it yourself.
It clearly wasn't "slavery" that was causing the invasion and fighting."

According to their own documents it was indeed protecting slavery that drove Fire Eaters to declare secession & war against the United States.
In the act of waging war Confederate forces invaded a dozen Union states & territories.

The US Congress made slavery a war issued in 1861 when it declared runaway Confederate slaves "contraband of war".

So it was "all about" slavery, from Day One.