re: was Jefferson Davis guilty of treason?

There's a lot of post-war revisionist thinking in this thread.

The Union held no moral high ground - not as we understand it today at least. Racism was endemic in the North and abolitionists were considered extremists. The Emancipation Proclamation was a military act, designed to reduce the manpower of the Confederacy. It did not free slaves in the Union. Most in the North considered free labor morally superior to the southern slave economy, but they made a distinction between the morality of free labor - and the worth of Blacks. They were no better than southerners in that regard and northerners worried that freeing the slaves would result in black immigration into the north. Lincoln himself proposed sending black Americans back to Africa.

The war itself was precipitated by Republican electioneering. National parties up to that point were crafted to draw broad support both north and south of the Mason Dixon line. The Republicans were not, they were a strictly sectional party drawing support from the Midwest and New England. Southerners were deeply worried by their election rhetoric and feared that Republicans would freeze them out of power. That was legitimate concern.

Finally, before the Civil War the states were considered fully sovereign entities that were in no way inferior to the federal government. Before the war writers used the expression "These united states." Only after the war did it become "The united states." The difference is important. Instead of coequal members, they became subordinate members of a permanent federal union.