The Southern congressional delegation did not unite behind Calhoun’s words as he hoped. But Calhoun could go over the heads of his fellow politicians. His Southern Address achieved considerable popularity in the South and an all-South convention might form the united front he wanted, either to stop the Wilmot Proviso or to take the South out of the Union.
South Carolina radicals (which, to those outside the state, included Calhoun) had good reason to look askance at their fellow Southerners. In the past Carolina got out ahead of the South and expected it to follow only to find other slave states unmoved. Likewise the rest of the South had good reason to look askance at South Carolinian radicalism, as the Palmetto State’s political spectrum often ran only between when secession should happen instead of if it ought to.
The call for a Southern convention could not, then, come from South Carolina. Fortunately for Calhoun’s hopes, the club of slave states where slaves outnumbered free people had another member in late 1849: Mississippi. It called the Mississippi Slaveholders Convention, with the understanding that its South Carolinian instigators would lay low. The Mississippi legislature appropriated $20,000 ($532,618.77 in 2011 dollars) and $200,000 ($5,326,187.75 in 2011 dollars) for the defense of the state should the Wilmot Proviso become law.
Meeting in October of 1849, the Mississippi Convention called for an all-South convention to meet at Nashville on the first Monday of the following June. The call itself put pressure on Congress to find a solution. The Nashville Convention added more. With the South gathered, Southerners might unite behind a plan to secede together. Few Southerners at the time believed a lone state had much of a future outside the Union, but the region as a whole surely would. Virginia fire-eater Edmund Ruffin wrote as much: “If the Convention does not open the way to dissolution, I hope it shall never meet.”
To Nashville came not a single Border State delegate. Louisiana’s moderate legislature refused to send delegates, as did North Carolina’s. Florida nearly joined them in abstaining. Texas sent only Sam Houston, always a moderate on slavery. Alabama sent delegates, but instructed them not to consider disunion. When called to elect delegates, ninety-five percent of Georgia voters stayed home. South Carolina alone supplied a full delegation that included many influential state politicians, but they maintained their low profile from the Mississippi Convention.
Deep South moderates dominated Nashville, denouncing Clay’s measures (introduced between the Mississippi and Nashville conventions), the Wilmot Proviso, and endorsing the plan to extend the Missouri Compromise line once more. They adjourned on June 12, taking a wait and see approach to the debates in Washington.