Events have transpired to result in a civil war. The key issue of the conflict is whether the federal government should have power, or the individual states. Rights for minorities and human rights are also an issue.
The success of the federal government in the civil war depends on a blockade of ports of entry to the rebels. If the feds continue to look strong in the borders and in battle, this will tend to keep foreign interests at bay so that the rebellion can be crushed.
Unfortunately the battles go poorly. The North loses ground and tens of thousands of soldiers. Despite greater numbers of troops and equipment, the North cannot find a general willing to apply this force consistently and effectively. The result is a series of losing efforts costing support for the war as well as lives.
It is the time of greatest desperation in the North. A former general is running against Lincoln in the election and the election could turn into a vote for Lincoln and the Union or a vote to allow the South to go it's way. Lincoln faced his own personal crises. See Lincoln and God, Strength for Anxious Days
In a science fiction, WHAT IF, twist of fate, Great Britain decides to enter the conflict, at least with naval forces to defeat the federal blockade (see Staying Power). The South goes into great debt, but their lack of manufacturing facilities is soon replaced by a steady stream of the finest weaponry. The fall of Washington DC leaves chaos and the government is dispersed. The remainder signs a treaty ending the war and the South goes its own way.
Of course, once the state have their own rights, they soon form their own countries. Western states and those on the frontier vie for new territories. Foreign interests again become ever a part of the state's increasing sets of problems.
My point hopefully is made about what could have happened with the United States. There is more to reflect on however.
Political situations have gone nuclear and religious and contagious in the region.
Kennedy noted that "The great battleground for the defense and expansion of freedom today is the whole southern half of the globe." Now that the Soviet Union has been defeated, the battleground has grown to the northern half as well.
Granted that communism was and still is a major menace, but a greater menace is arising. It has to do with not respecting any form of government or any authority at all. It rises in our own nation and nearly all others. It rises with fatherlessness, disrespect of other beliefs or religions, intolerance, and tolerance of abuse.
Although Reagan and Afghanistan and internal forces may have collapsed the Soviet Union, the resultant world has become even more frightening.
Restoration of Communities, Nations, People: Role of Rural Family Docs