The idea expressed by President Lincoln in the excerpt is; The Union exists only through the consent of sovereign states.
The excerpt reads thus;
It therefore follows from the excerpt above that President Lincoln's idea connotes that Union exists only through the consent of sovereign states.
Remarks;
The Union exists only through the consent of sovereign states.
The Union requires a nationwide decision on slavery.
The Union matters more than the current disagreements between states.
The Union will be preserved through military force if necessary.
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