Sentence:  All the captives, the innocent as well as the guilty, gladly subscribed to the terms; for they found themselves in a temporary duresse which did not admit of any fair argument of the merits of the case, and there is no <WSD>leveller</WSD> so effectual as a common misfortune. 
Meaning of the word marked with <WSD> tags:  ("especially") Something that transcends people's differences (such as social class, wealth, etc.); something that tends to eliminate advantages and disadvantages.