Were Southerners "rebels" in seceding from the Federal Union?

 

April is Confederate History and Heritage Month in the Old Dominion, as well as in many states across the South. As part of the celebration, and in an effort to educate the citizens of the Commonwealth, we will present a Q&A each day, from a Confederate Catechism, by Lyon Gardiner Tyler, 1853-1935; the son of President, John Tyler, who also was a member of the Confederate congress. He was a professor of literature at the College of William and Mary, and served as President of the College of William and Mary from 1888 until 1919.
Day 13:

16. Were the Southerners "rebels" in seceding from the Federal Union?

The term "rebel" had no application to the Southern people, however much it applied to the American colonists. These last called themselves "Patriots," not rebels. Both Southerners in 1861 and Americans in 1776 acted under the authority of their State governments. But while the colonies were mere departments of the British Union, the American States were creators of the Federal Union. The Federal government was the agent of the States for the purposes expressed in the Constitution, and it is absurd to say that the principal can rebel against the agent.

President Jackson threatened war with South Carolina in 1833, but admitted that in such an event South Carolinians taken prisoners would not be "rebels" but prisoners of war. The Freesoilers in Kansas and John Brown at Harper's Ferry were undoubtedly "rebels," for they acted without any lawful authority whatever in using force against the Federal Government, and Lincoln and the Republican party, in approving a platform which sympathized with the Freesoilers and bitterly denounced the Federal Government, were rebels and traitors at heart.