[Idabilly]

Resolved by the Senate and House of Representatives of the United States of America in Congress assembled, That the following article be proposed to the Legislatures of the several States as an amendment to the Constitution of the United States, which, when ratified by three-fourths of said Legislatures, shall be valid, to all intents and purposes, as part of the said Constitution, namely:
ART. 13. No amendment shall be made to the Constitution which will authorize or give to Congress the power to abolish or interfere, within any State, with the domestic institutions thereof, including that of persons held to labor or service by the laws of said State.

—12 United States Statutes at Large, 36th Congress, 2nd Session, 1861, p. 251.

How true - it was.......
“As for the South, it is enough to say that perhaps eighty per cent. of her armies were neither slave-holders, nor had the remotest interest in the institution. No other proof, however, is needed than the undeniable fact that at any period of the war from its beginning to near its close the South could have saved slavery by simply laying down its arms and returning to the Union.”
Major General John B. Gordon

[Non-Sequitur]

ART. 13. No amendment shall be made to the Constitution which will authorize or give to Congress the power to abolish or interfere, within any State, with the domestic institutions thereof, including that of persons held to labor or service by the laws of said State.

And the rebel government not only incorporated all those protections into their own constitution, along with guaranteeding that no confederate state could ever be slave free. Then they went a step further and protected slave imports as well.

“As for the South, it is enough to say that perhaps eighty per cent. of her armies were neither slave-holders, nor had the remotest interest in the institution. No other proof, however, is needed than the undeniable fact that at any period of the war from its beginning to near its close the South could have saved slavery by simply laying down its arms and returning to the Union.”

Well not after January 1863 they couldn't. But Gordon's post-rebellion revisionism aside, depending on the state upwards of half of all Southern soldiers either owned slaves or came from families that did.