Here's a different appraoch to the issue of what provoked the war. Few people mention the impact of Harpers Ferry, notable as an early example of religious terrorism on the North American continent. Up until the fall of 1859, most Southern citizens believed that the slavery issue could be debated reasonably and that abolitionists were an inconsequential fringe element. Subsequent events, such as the revelation that prominent men in the North had financed John Brown's arms purchases and the outburst of sympathy for Brown following his trial and execution, demonstrated strongly otherwise.
From our perspective, Harpers Ferry seems to have been an isolated event, an aberation of sorts. The Senate investigation and other evidence suggested that this was just the first of several planned attacks against Southern states.
As one Southern editorial writer stated, it's time we recognize that these people intend to murder us and our families in our beds.
By the way, abolitionists were well aware of the points raised by Mr. Hines in his editorial and believed a government which sanctioned slavery to be immoral and unworthy of allegiance or support.
Seeing that the Federal government could not or would not respond forcefully to future attacks, Southern state governments took matters into their own hands. For example, the Alabama state legislature immediately organized a volunteer militia system expressly to respond to future abolitionist threats. The legislature also enacted a fail-safe provision that in the event of the election of a Northern sectional candidate as POTUS, a convention would be assembled to reconsider Alabama's relationship to the Federal union. Southern governors called on the Secretary of War to issue their quota of firearms to U.S. armories in their states, and sent agents to New England to purchase modern firearms from manufacturers there.
None of this would have taken place without the help of John Brown, abolitionist extraordinaire.
Harpers Ferry is the missing element in the debate as to what brought the war about. Leaving Harpers Ferry out of this discussion is like trying to explain American foreign and domestic policy during the past nine years without mentioning 9-11.