the disaster at Appomattox.
The disaster was the firing on Fort Sumter. If that had not happened, there would have been no Appomattox.
“If that had not happened, there would have been no Appomattox.”
If the Declaration of Independence had not happened, there would have been no Appomattox.
So what does your statement mean?
Nothing.
The disaster was allowing a big city progressive troublemaker to cheat in the Chicago primary. Seward would not have started a war that killed 750,000 people.