John Calhoun and his like-minded supporters hoped that nullification would become a legitimate alternative to secession for the South. Nullification was the doctrine that Calhoun believed meant that states could nullify a federal law, on the basis that states had their own sovereignty and the federal government could not infringe on that sovereignty. See Daniel Walker Howe, What Hath God Wrought: Transformation of America, 1815-1848, 402. This approach was designed to primarily perpetuate the institution of slavery, without the conflict culminating in secession, or worse, civil war.
Last Best Hope of Earth 