Baltimore was Nancy Pelosi's birthplace and her family was engrained in the local politics, her father being mayor. Perhaps this resignation has something to do with family ties.
-Pelosi was born in Baltimore to an Italian-American family
-her father was a Democratic Congressman from Maryland
-he became Mayor of Baltimore
-Pelosi's brother, Thomas D'Alesandro III, also a Democrat, was Mayor of Baltimore from 1967 to 1971
https://en.wikipedia.org/wiki/Nancy_Pelosi