Quote 4
"My husband, fellow-citizen, is a good Republican and a bold man; he has deserved well of the Republic, and possesses its confidence. But my husband has his weaknesses, and he is so weak as to relent towards this Doctor." (3.14.4)
Madame Defarge’s loyalties are more complicated than the sort of family-centered loyalties we see in the Manettes. Sure, she likes her husband and the revolution. She cares more, however, about her own revenge.
Quote 5
There was a character about Madame Defarge, from which one might have predicated that she did not often make mistakes against herself in any of the reckonings over which she presided. (1.5.20)
Madame Defarge becomes her own form of judge and jury over the course of the novel. Her version of justice, which demands unremitting revenge, could be seen as the downfall of the new Republic as a whole.