Sentence:  ... whereas, ten years since, there were thousands who could not endure my lightest word of rebuke to the South, they can now easily swollow John Brown whole, and his rifle into the bargain. In firing his gun, he has merely told us what time of day it is. It is <WSD>high noon</WSD>, thank God! 
Meaning of the word marked with <WSD> tags:  A time, set out in advance, at which an important decision is to be made or a nemesis is to be confronted