Each candidate has a successful political playbook for reference. Eight years ago, Robert L. Ehrlich Jr. inspired enough support in Democratic Maryland to win a governor's office his Republican party hadn't occupied in a generation. Four years ago, Baltimore's Democratic mayor, Martin O'Malley, toppled a governor so popular that his approval rating had never dipped below 50 percent.
But these 2010 gubernatorial hopefuls each face new hurdles if, as expected, they turn away challengers in the Sept. 14 primary. O'Malley is seeking the support of an electorate that has tired of incumbents. Ehrlich is himself a longtime politician, with a long record to defend.