Nonsense
The founders envisioned a Union of the colonies.
That's why the formed a Continental Congress.
That's why they made sure that the Declaration of Independence was an acceptable document to all the colonial delegations.
That's why the Articles of Confederation were adopted.
That's why the elements of the Articles that weakened the Federal Union were replaced soon after with a more strongly Federal document.
None of the prominent Americans whom we consider the Founding Fathers: Washington, Jefferson, Franklin, Adams, Jay, Hamilton, Madison, Morris, etc. contemplated a divided America as anything other than a tragic end to the cause.
Your implied contention, that the Founders either envisioned or desiderated a divided America is itself nonsense.
The founders, in founding, had seceeded. It was a recognized concept (take that DoI preamble) that a state could seceed. There were strong movements in both the middle and northern states FOR secession. Lincoln was not universally loved, he suspended Habeus Corpus for the duration of his presidency, and imprisoned thousands of people with "disenting" points of view. He closed news papers, and just after they were elected, rounded up and imprisoned a double handful of merry-lander state congresscritters because they'd made pro-middle-states-secession noises during their campaigns.
Nope I am no Lincoln hating cracker. I have nothing but contempt for those who took the most perfect guideline for creating a government, one that protects individual volition, responsibility, and property, and basically uses it for toilet tissue. Lincoln did great harm to the constitution. We are a lesser country because of it. Fortunately enough of the overall concepts have survived for us to be the greatest nation the world has ever seen (relative to INDIVIDUAL LIBERTY).
Washington=good
Lincoln=bad
Reagan=good
W=Good (needs work to get away from Henry Clay federalism, but we can work with him on that!)
God's speed
Semper Fidelis,
Sic Semper Tyrannis