Then-Maryland Gov. Martin O’Malley addresses the Democratic National Convention in Charlotte on  Sept. 4, 2012. (J. Scott Applewhite/AP)

Maryland Gov. Martin O'Malley (D) said Sunday that there should be more than one person running for the Democratic nomination, while acknowledging that he has a "tremendous amount of respect" for Hillary Clinton.

"I believe that if you have the executive experience, the ideas to serve our nation well, and the ability to govern, you should offer your candidacy and let the people decide," he said on CBS's "Face the Nation."

He said that he's "seriously considering" running and will make up his mind by May but that he wasn't sure why others have not come forward.

When asked by host Bob Scheiffer why he thought he would be a better president than Clinton, O'Malley said it was because of "the experience I can bring to the job."

"I have 15 years of executive experience as a big-city mayor and as a governor," he said, guiding the state through a recession and "doing difficult things like passing marriage equality" and the Dream Act.