I haven't seen any evidence whatsoever to support this thesis. The people within Virginia, Tennessee, N. Carolina, etc. were already in heated debates over secession, they might have eventually seceeded anyway. Lincoln did pretty much all he could just to keep Maryland, Kentucky, and Missouri from seceeding.
Unfortunately, rational discussions weren't of much use in late 1960 and early 1861, nobody was listening to each other. Many southern newspapers refused to even print Lincoln's inaugeral address, instead printing their own editorial opinion of what a "vile speech" it was - the ordinary southerners had little opportunity to form their own opinion.