Twenty years ago, Martin O’Malley was an up-and-coming law student when then-candidate Barbara Mikulski chose the Montgomery County native to be the field director for a campaign that would ultimately result in Maryland’s first female Democrat in the U.S. Senate.

“He was in it because he was very idealistic,” Mikulski said last week during a phone interview. “He wasn’t going to law school to join a big firm. He wanted to fight for justice. He was a fighter. He wanted to stand up for the little guy.”