It comes up tangentially in Gene's comment section, so here's a thought.
Thought one: I think it's right to say that slavery was "the cause" of the Civil War. It's not "the cause" in quite the simple way that a lot of people try to make it. States' rights did matter a great deal. But they only mattered because slavery mattered, and they only really mattered because of Southern paranoia. None of the measures actually taken or threatened (fights over the Fugitive Slave Act, restricting expansion of slavery into the territories) actually threatened states' rights by any reasonable definition of states' rights. So the point is, let's not act like states' rights is some goofy idea - it's not. But it was invoked in an unthoughtful way because of paranoia over a very bad cause, which is of course slavery.
Thought two, and I think over the different scenarios with this one a lot: Virginia, along with North Carolina, Tennessee, and Arkansas were not unthoughtful invokers of states' rights or paranoid in the way that South Carolina, Alabama, Mississippi, etc. were. If the Union had just marched on under Lincoln with these states in tow, slavery would have probably died out even quicker and the deep South would have become even more backwards a backwater than it actually did become. But then "the Union" and the Constitution that cemented it wouldn't mean all that much. So one of the most tragic facets of all of this for me is this between-a-rock-and-a-hard place situation with Virginia, North Carolina, Tennessee, and Arkansas who I think it's always important to remember were a part of the Confederacy for different reasons than the deep South.
Thought three, which is incredibly cliche and probably fairly careless for a non-historian to bandy about, but I do get uncomfortable when people act as if Confederate opinion was homogenous, particularly among the rank and file. That strikes me as nonsense, and even if you can find enough letters from soldiers including enough pro-slavery lines to cobble together an article about how the rank and file were big time supporters too, it's not clear to me at all that they aren't pawns for the most part or that they bear the same sort of moral culpability as the leadership of the deep South. People are impressionable. In and of itself that's not a very ringing endorsement, but it's just to say that under different circumstances (perhaps, as I alluded to above, circumstances where Virginia and other states stayed in the Union) these same rank and file could very easily have been sitting in their own homes muttering about how ugly an institution slavery was and how foolish the deep South was to march out of the Union over it.
Anyway, this whole period is extraordinarily depressing to me, which is why I prefer to read about things that went on before or after it myself. That's probably not the best solution, but it's my solution.