That sounds good, but who decides? The people of the South thought that the Federal Government no longer was going to protect their property rights, just as strongly as abolitionists thought that the Federal Government was needed to enforce the rights of the slaves living there. The Federal Government itself can't be allowed to decide, for obvious reasons. It's a tough question.
Cleo
Hehe, good question. And honestly, I think this is a question which can only be settled in a court of arms, just as our Revolution was.
In the case of the American Revolution, it was clear what was happening: the English government was violating the rights of the American colonies and its citizens, and because of the way the government was set up, the colonies had no real chance of ever affecting change. They were stuck, sending non-binding and useless petitions that weren't worth the paper they were printed on. And so they rebelled, and ultimately won their freedom.
Ultimately, I'd say the People retain the right to control their government, which includes the right to overthrow it, or secede from it. So I would say that the People are the ones that decide when their rights are being violated so seriously, and that no legitimate method of redress remains. And I think this works both with the Revolution, and with the Civil War.
At the time of the American Revolution, there was a big split in public opinion in the Colonies: to rebel, or stay loyal? But as far as I can tell, that was the main difference - most of the Tories (Or loyalists) agreed that many of the things the English government were doing were unfair. They just didn't believe that they had the right to rebel. Even in England, a good many people - from Dukes to merchants and on down - believed that good King George was needlessly provoking and abusing England's "children." Not all Englishmen thought so, but a good portion did, and an even greater portion in the Colonies.
Now look at the Civil War. The South, the part that seceded to form the Confederacy, did indeed think that their rights were being violated. And I would submit to you that most Southerners really were more concerned with states rights than slavery itself - see the Nullification Crisis during the term of Andrew Jackson, where South Carolina (Of all states!

) very nearly led to secession and open war. And yes, Southerners believed that their rights were being violated - but the idea that Northern states banning slavery was a violation of
Southern rights was a view pretty much confined to the South. (Northern Democrats commonly opposed the war - but few truly insisted that the South was truly in the right. Just that they had the right to secede, and that it wasn't worth fighting over.) It wasn't a nation that tried to secede, but an aggrieved minority.
Furthermore, it was not that the South had no means of redress, but that they didn't like the outcome. They voted freely and fairly in the election of 1860. And they lost, and in response, several states seceded. If they had seceded because the election was rigged, then they might have had a good argument - after all, there can be no redress for wrongs by the national government, when it is controlled by the abusers. But that's not what happened - Abraham Lincoln was elected fairly, and the South seceded
because they didn't like it. This was not a revolution against a tyrannical government which refused to leave open an ally where change could be effected. This was a rebellion against lawful authority
because a minority got outvoted. That, I think, is the crucial difference. They rebelled not because they had no other option, but because they didn't get their way. Thus, I see a crucial difference between the American Revolution and the Civil War, and I think therein lies the reason for the justification of one but not the other.
Well....that was pretty long.

I can get rather long winded when I get going. Do you see my basic point, though? If you need clarification or have issue with my historical knowledge (Which I admit is woefully incomplete) then please do so.
Also, note that I'm only talking about secession from an unwilling American Union. If the rest of the nation is willing to let you go, then I do think that should be allowed. What I'm opposing is unilateral secession.