According to the Declaration of Independence -and elements
of the US Constitution -they very clearly had a right to secede. As we we still do today. One must accept the consequences of ones actions though. I am deeply offended that any carpetbagger would charge them all with Treason.
Lee and others were schooled in th emilitary academies who
were not as harsh-- but understood a mans natural desire
to defend his home--and State from agressors.
The arguement can be made that the states had the right to secede. But the question is did those southern states have a right to unilaterally secede without the approval of a majority of those affected by their actions? I don't think that they did.