Or to take a less grievous matter: it has been supposed by some that "The Scouring of the Shire" reflects the situation in England at the time when I was finishing my tale. It does not. It is an essential part of the plot, foreseen from outset, though in the event modified by the character of Saruman as developed in the story without, need I say, any allegorical significance or contemporary political reference whatsoever.
I don't understand the part in bold above. Can anyone help me with it?