Synthesized answer
The provided passage from "The Great Democracies" by Winston S. Churchill does not contain information about the specific evidence the author provides. It is only the title of the work and the author's name. Therefore, I cannot answer what evidence the author provides based on this passage.
Synthesized from the book passages below. Chat with the book on Feynman for follow-up.
From the book
Title: The Great Democracies [A History of the English-Speaking Peoples, Volume Four]. by Winston S. Churchill