Some sure did:
"Our position is thoroughly identified with the institution of slavery - the greatest material interest of the world." -- Mississippi Secession Declaration
Upthread we were discussing Robert Rhett and the two tracts he ran out on secession. One, the invitation to the other States to secede, which he wrote at the instigation of the secession convention, reads like a political-science text; but the newspaper editorials he ran out about the same time, or a few months earlier, talk about the economic impact of slavery, the value of slaves, and so on, emphasizing it to a great degree. And yet slavery wasn't even among the top two capitulations of his address to the other States' secession conventions.