Barbara Mikulski, the senior United States Senator from Maryland and a member of the Democratic Party, has announced her retirement. Mikulski is also the longest-serving woman in Congress. Back in 1976, she was first elected to the House and after 10 years she was elected to the Senate.

On Monday, Maryland Sen. Barbara Mikulski has made announcement about her plans to retire. If Martin O'Malley, had any doubts about running for president against Hillary Rodham Clinton, now he has a possible choice. The team of the ex-governor refused to engage in talk on Monday.

The ex-governor has yet to achieve much traction in a hypothetical matchup against Clinton. Clinton has a network of super PACs already working on her behalf and also a lot of the party's establishment excitedly waiting for her to make an announcement about her candidacy.

Allies of O'Malley said that he has always liked his role of executive and also enjoyed. He served as the 61st Governor of Maryland, from 2007 to 2015. He also has shown some interest in the past in serving in Congress.

Political reputation of O'Malley hit in the November elections, at that time Republican Larry Hogan defeated his hand-picked choice in order to replace him in Annapolis. The ex-governor biggest potential competitor is Rep. Chris Van Hollen. Hollen is the top Democrat on the House Budget Committee.

"It's going to be a very competitive field. There is going to be an incentive for a candidate to announce earlier rather than later to build support as soon as you can", said Oscar Ramirez, a former vice chair of the state Democratic Party.