“What ideology was the unlimited central power trying to impose on the South?”
Love and respect for the union . . . by bayonet.
And effective dominance of the nation’s economic and political system by the industrial states for at least 100 years. In other words, money.
Well that's ridiculous because the article this thread is linked to gave that as a reason for secession in the first place. You're talking about the Confederacy losing its war.