Slavery was the main reason that the Southern leadership wanted to secede from the Union, and they were willing to go to war over their right to secede.
That seccession was the main reason that the Northern leadership was motivated, and they were willing to go to war to prevent the South's seccession.
Why was the north trying to prevent the south's succession?
The Northern leaders most likely had some financial and political reasons for wanting to prevent Southern seccession. Lincoln was also reportedly a firm believer in 'the American experiment' and he wanted to preserve the Union at all costs. He reportedly felt like the fracturing of the Union would be detrimental...not only to the Union...but also to 'the American experiment' as a model for others.
Your correct, the north did have financial (economical) reasons for wanting to keep the south from succeeding. The south produced about 75% of the nations economy and the northern economist/politicians knew they couldnt survive, without the south.
Doesnt get much simpler than that... just follow the dollar!
