[DiogenesLamp]

Well, if that’s true we can dismiss forever the notion that the North fought the war for some high moral cause like “freeing the slaves.”

They aren't going to give that up. It's the only "moral" reason for which they can sort of justify all the blood that was spilled.

It is their fig leaf.

[BroJoeK]

jeffersondem: "we can dismiss forever the notion that the North fought the war for some high moral cause like 'freeing the slaves.' "

DiogenesLamp: to jeffersondem: "They aren't going to give that up.
It's the only 'moral' reason for which they can sort of justify all the blood that was spilled.
It is their fig leaf."

Far more than mere "fig leaf", fear of Lincoln freeing the slaves drove Deep South Fire Eaters to declare secession and ultimately war on the United States.
Emancipation and abolition were also strong motivators for many Republicans (but not Democrats) and became more so as the war dragged on:

Johnny Cash sings Battle Hymn of the Republic

Or, if you prefer, Elvis Presley

This one doesn't say, but sounds like a Mormon Tabernacle Choir version.
If you watch carefully, you'll see references to the Iron Brigade & Irish Brigade as well as the 54th Massachusetts "Glory" regiment.