Discuss Dr Manette's role in protecting Darnay. How did Dr. Manette have such influence?

Manette must protect the prisoner and his family, when Lucie once protected the prisoner. In his power as temporary head of the family, Dr. Manette must protect Lucie, but he also does it to repay Lucie for her own loving care. In short, he is a new provider of magic: he protects Darnay and Lucie, and he motivates the mobs to peace. He has done precisely what the weak Darnay wanted to do, but could not.