Well, you're consistent, if silly.
The cause of conflict would have been the same issue that had caused problems (and threats of war) for 40+ years before the Civil War actually broke out: the status of slaves in lands to the west. The Missouri Compromise, Clay compromise, and Kansas/Nebraska act were all failed attempts to resolve fundamental differences over whether new territories and states were to be slave or free.
Had the South won the Civil War, then the competition over slave vs. free would have been sharper than before the war, and a second war would have been likely.
The second war, like the first, would have been about the South's unwillingness to do away with slavery. That's just the fact, whether you like it or not.
chattel slavery would have died an UNlamented death within 10-15 years MAXIMUM (my guess is 5-10 years) according to most scholars of Agricultural Innovation & the Industrial Revolution.
the FIRST WBTS was NOT about slavery either. it was nothing more or less than a war to "preserve the union" (for the North) OR a war for LIBERTY & SELF-determination (for Southrons).
BOTH lincoln, the tyrant AND US Grant said that the war was ONLY about PRESERVING the UNION. (NEITHER wanted to free the slaves. in point of fact, BOTH were stone racists of the robes & hood sort.)
sorry, but that too is FACT.
free dixie,sw
Due to industrialization and increasing numbers of European immigrants, the North would had crushed the South in the second war.