Powerful U.S. Sen. Barbara Mikulski (D-Md.), the longest-serving woman in the history of Congress, will not seek a sixth term, she announced Monday.
Mikulski, 78, made the announcement during a press conference in Baltimore's Fells Point neighborhood, saying she wanted to focus on serving the people of Maryland rather than running a re-election campaign.
She stressed that she will remain through the remainder of her term in December 2016.
"...[R]emember, for the next two years, I will be here, working the way I do, 100 percent," she said. "And when this term is done, I will know that I have given it my very best shot."
Race to Replace Sen. Mikulski Should Be Interesting
She thanked Sen. Ben Cardin, the junior senator from Maryland, "for being the best partner," and former Sen. Paul Sarbanes. She also thanked her staff, saying "I know [they] will be answering the phones to say, 'What the hell did she just do?'"
Of any plans for after retirement, "I haven't thought that far," Mikulski told a reporter. "This was a very big decision."
Mikulski would have been up for re-election next year. Until Monday, she had declined to say whether she would run for another term.
"I want the people of Maryland to know there is nothing gloomy about this announcement," she said. "There's no health problem; I'm not frustrated with the Senate. The Senate will always be what the Senate is."
Mikulski became the longest-serving woman in the history of Congress in 2012. A Baltimore native, she started out as a social worker and was elected to the U.S. House in 1976, where she served 10 years before winning a Senate seat in 1986, according to a biography on her website.
She headed the Appropriations Committee until the new Senate was seated in January with Republicans in charge.
RAW VIDEO: Mikulski Announces Decision to Retire
In a 2014 interview, Mikulski said her approach as chair of the Appropriations panel was "to focus with civility and courtesy. Old school values. Don't do surprises or stunts and negotiate directly and not through the press."
Senate Republican Leader Mitch McConnell described Mikulski at the time as forceful and results-oriented. "I think she's terrific," he said.
Mikulski had been seen as more engaging and approachable than her predecessors as appropriations chairman, the late Sens. Robert C. Byrd, D-W.Va., and Daniel Inouye, D-Hawaii. She had spent decades honing relationships with members of both parties, learning their needs and end goals.
After a short tenure as chairman, she now is the top Democrat on the panel after Republicans captured control of the Senate in last November's elections.
"She knows that if you know somebody and what they want, you can help them be successful. And when you help people be successful, Republicans or Democrats, that's how you move bills," said Democratic Sen. Patty Murray of Washington, a Mikulski protege.
In a 2014 interview, Mikulski said her approach as chair of the appropriations panel was ``to focus with civility and courtesy. Old school values. Don't do surprises or stunts and negotiate directly and not through the press.''
Mikulski has also been an active advocate of equal pay for women. The Maryland senator sponsored legislation last year aimed at tightening a 1963 law that made it illegal to pay women less than men for comparable jobs because of their gender. But Senate Republicans blocked the bill in an April 2014 floor showdown.
"When I hear all these phony reasons, some are mean and some are meaningless, I do get emotional," Mikulski said of arguments against the legislation. "I get angry. I get outraged. I get volcanic."
Mikulski played off former CIA Director Michael Hayden's recent comment that Senate Intelligence Committee Chairwoman Dianne Feinstein, D-Calif., was motivated by "emotional feeling" when she sought an investigation of the spy agency's harsh treatment of terrorism suspects.
She is the second powerful female Democrat to announce her retirement from the Senate in recent weeks, after California's long-time Sen. Barbara Boxer announced in January that she would not seek re-election in 2016.