His advisers note he created a civilian review board for police conduct, expanded drug treatment and saw a decline in excessive force complaints and police-involved shootings.

After two terms as mayor, he won two terms as governor with strong support in Baltimore.

"The people of Baltimore were given ample opportunities to express at the ballot box their satisfaction or dissatisfaction with the direction that our city took to reduce violent crime, to reduce homicides, to make our city more livable," O'Malley said.