Democrat Sen. John C. Calhoun from South Carolina
Secession a "constitutional right":
Rockingham #462: "Andrew Jackson, who was President at the time, warned on May 1, 1833, that 'the tariff was only a pretext, and disunion and Southern confederacy the real object.
Rockingham #478: "I recommend that you read "The South as a Conscious Minority, 1789-1861: A Study in Political Thought" by Jesse T. Carpenter.
The next pretext will be the negro, or slavery question.' "
He traces the development of the compact theory of the Constitution and of the South as beleaguered and put upon as providing the legal and moral justification for secession.
Once such thinking became current in the South, secession became a clear possibility in the region's political thought.
An unpopular war, a disputed presidential election, tariffs, slavery, or some other cause could then provide the pretext, to use Jackson's term."
FLT-bird #479: "I'll check that out.
The South clearly did feel beleaguered and put upon.
Its difficult to argue they weren't.
I think the Tariff of Abomination was the first really big traumatic shock to Southerners.....that their economy could be wrecked for entirely political/artificial reasons to benefit the corporate interests in the Northeast.
That was immediately followed by a 30 year long struggle for political power which the Southern states could see they were losing due to mass immigration in the North."
Naw... first, Calhoun's argument is 100% complete bullshite and, second, contrary to FLT-bird's claims, "the South" felt no such thing in 1830 or later.
Yes, in the 1830s, Southern-Democrat elites who ruled South Carolina asserted their authority to nullify national laws they disliked, and to declare secession as a "constitutional right".
But "the South" included states like Pres. Jackson's Tennessee and Whig Sen. Henry Clay's Kentucky, none of which tolerated Calhoun's bullshite nonsense:
Pres. Andrew Jackson from Tennessee
"I'll hang you for it":

Nah. The repeated statements of Southerners especially in the 1850s and and the early 1860s shows that they very much did feel that way.
Yes, in the 1830s, Southern-Democrat elites who ruled South Carolina asserted their authority to nullify national laws they disliked, and to declare secession as a "constitutional right". But "the South" included states like Pres. Jackson's Tennessee and Whig Sen. Henry Clay's Kentucky, none of which tolerated Calhoun's bullshite nonsense:
South Carolina, being more impacted by the Tariff of Abomination, was more vehement against it. Other Southern states sympathized but weren't willing at that time to go to the same lengths to nullify the tariff. Obviously the 7 states of the Deep South had reached a different conclusion by 1861.
Sen. John C. Calhoun (South Carolina): "each state, being sovereign, possessed “the constitutional right peacefully to secede” if its nullification were overturned by amendment." Pres. Andrew Jackson (Tennessee): “Secession, like any other revolutionary act, may be morally justified by the extremity of oppression; but to call it a constitutional right is confounding the meaning of terms.” Jackson, Clay and many other Southerners were exactly right, while Calhoun, FLT-bird, DiogenesLamp and all such are 100% full of Democrat bullshite.
Whereas I'd say you are wrong and are full of Lincolnite Bullshite.
"We, the delegates of the people of Virginia, duly elected in pursuance of a recommendation from the general assembly, and now met in convention, having fully and freely investigated and discussed the proceedings of the Federal Convention, and being prepared as well as the most mature deliberation hath enabled us to decide thereon, Do, in the name and in behalf of the people of Virginia, declare and make known that the powers granted under the Constitution being derived from the people of the United States may be resumed by them whensoever the same shall be perverted to their injury or oppression, and that every power not granted thereby remains with them and at their will...."
"We, the delegates of the people of New York... do declare and make known that the powers of government may be reassumed by the people whenever it shall become necessary to their happiness; that every power, jurisdiction, and right which is not by the said Constitution clearly delegated to the Congress of the United States, or the department of the government thereof, remains to the people of the several States, or to their respective State governments, to whom they may have granted the same; and that those clauses in the said Constitution, which declare that Congress shall not have or exercise certain powers, do not imply that Congress is entitled to any powers not given by the said Constitution; but such clauses are to be construed either as exceptions in certain specified powers or as inserted merely for greater caution."
"We, the delegates of the people of Rhode Island and Plantations, duly elected... do declare and make known... that the powers of government may be resumed by the people whenever it shall become necessary to their happiness; that every power, jurisdiction, and right which is not by the said Constitution clearly delegated to the Congress of the United States, or the department of the government thereof, remains to the people of the several States, or to their respective State governments, to whom they may have granted the same; that Congress shall guarantee to each State its sovereignty, freedom, and independence, and every power, jurisdiction, and right, which is not by this Constitution expressly delegated to the United States."