False.

Lincoln's lengthy and enormously influential Cooper Union speech, which propelled him into the nomination and the presidency, was entirely about slavery and stopping its expansion in the western territories.  The South attacked Fort Sumter and seceded shortly after he was elected.

It is absurd to think that hundreds of thousands of men hurled themselves against one another for four years over the finer points of tariffs and "states rights."  The Civil War was about eliminating slavery and stopping its expansion in the western territories.