O'Malley jumps into presidential race, offers progressive alternative to Clinton

Martin O'Malley launched his presidential campaign Saturday with an appeal to the party's progressive base that he hopes will upend the conventional wisdom that Hillary Clinton is destined to clinch the Democratic nomination.

The former Maryland governor unveiled his campaign in Baltimore, the city where he was once mayor -- a role that is central to his political persona. But his Baltimore credentials could become more of a challenge than he initially thought after a riot erupted in the city in April.