Martin O'Malley is a Maryland native who bas been in Congress since 1976 and a senator since 1987 . Democratic Reps. Chris Van Hollen and Donna Edwards , and former Govs . Mikulski and Bob Ehrlich , could all run to replace her . Martin O'Malley 's exit announcement came just weeks after a similar announcement from California Democratic Sen. Barbara Boxer .
Mikulski is a Maryland native who bas been in Congress since 1976 and a senator since 1987 . Democratic Reps. Chris Van Hollen and Donna Edwards , and former Govs . Martin O'Malley and Bob Ehrlich , could all run to replace her . Mikulski 's exit announcement came just weeks after a similar announcement from California Democratic Sen. Barbara Boxer .