Decision Quotes - page 18
I hope none who hear me will confound this expression of mine with advocacy of the right of a state to remain in the Union, and to disregard its constitutional obligations by the nullification of the law. Such is not my theory. Nullification and secession, so often confounded, are indeed antagonistic principles. Nullification is a remedy which it is sought to apply within the Union, and against the agent of states. It is only to be justified when the agent has violated his constitutional obligation, and a state, assuming to judge for itself, denies the right of the agent thus to act, and appeals to the other states of the Union for a decision; but when the states themselves, and when the people of the states, have so acted as to convince us that they will not regard our constitutional rights, then, and then for the first time, arises the doctrine of secession in its practical application.
Jefferson Davis