You are simply wrong about that. The Morrill Tariff was passed by the House in May of the previous year and was heading to passage in the Senate. Senator Robert M.T. Hunter of Virginia subsequently mustered every ounce of parliamentary procedure he could to delay the Senate vote until after the election on the slim chance that they could gather the votes to defeat it. But as Wigfall noted and Hunter later recognized when the winter session opened, the new incoming Senators (who would take office in March) with the soon-to-be added GOP members from Kansas would be even worse than the existing one. There best case scenario was to force a tie, in which case they'd lose anyway because of Hamlin. Hunter and the southerners spent most of December and January trying to delay the Morrill Bill to no avail. Hunter openly admitted that its passage was becoming inevitable even though he fought it on the floor to the bitter end.
The other members realized the situation as well and in late December several of the southern members drafted a letter back to their home states urging them to follow South Carolina's course.