Without the concept of natural law, there are no God given individual rights, only those that the gov't allows. Sort of like Linkum and the Souths "natural right" to secede/revolt against "intolerable oppression". The North and Linkum must have "accidentally" forgot about a people's "natural right" to rid themselves of bondage/oppression, be that real or percieved. No not at all, no more then the South forgot about the slaves right to rebel based on their 'natural rights'
But Calhoun had rejected the Declaration's view on all men being created equal and is this that makes the right to revolution a legimate one.
If you are going to deny others natural rights, do not expect yours to be upheld.