Martin O'Malley

You couldn't graduate from Catholic University of America (O'Malley's alma mater) without taking philosophy, ethics, and theology classes. But you could see already, even in a high school speech delivered by O'Malley (can't find the link at the moment), that he was already imbued with moral principle and a sense of justice. Of course, his parents had a lot to do with his character formation as well.

One trait that reveals his strength of character is his amazing self-effacing sense of humor. People who can laugh at themselves have great confidence and self-esteem. They are not looking for approval from others. They just strive to do the right thing. That's why O'Malley doesn't follow polls, but follows principle. The problem is that the Democratic party has a home-run hitter on their team, but they leave him on the bench and keep sending in the older players.