"When I came to the Senate, the senators were Tom, Dick and Harry. Now they're Barb, Tammy and Dianne and Heidi," Mikulski mused in an interview with CNN.

In 1986, when she was first elected, women weren't allowed to wear pants on the Senate floor. They lacked a proper bathroom. And, there were only two female senators then -- Mikulski and Nancy Kassebaum of Kansas.

The Maryland Democrat is now leaving as one of 20 female senators -- a bipartisan group that Mikulski is the unofficial dean of, gathering them all for monthly dinners.

"We disagreed on issues, but what we said was, No. 1, we were going to be a zone of civility even when we disagreed," she said.

Mikulski is the longest-serving woman in the history of Congress. Still, talking to us in one of her final interviews as a sitting senator, she made clear that she is retiring with unexpected sadness. On a scale of 1-10, she said her disappointment was a 52 on election night, after her old Senate colleague failed to become the first female president.

At first Mikulski demurred when asked whether America was just not ready for a female president, responding that she will "let the history books write about that."

When pressed, she said of Hillary Clinton: "There were a lot of biases against her."

"You know what we find when you break the glass ceiling? You end up living in a glass office. Where everything you do is scrutinized," she said.

It's not just Mikulski's feminism that makes Clinton's defeat so crushing. It is that her own Democratic Party lost touch with the kind of working-class voters she says she never stopped fighting for.

"People right now in Baltimore that have three part-time jobs," said Mikulski. "Many of my constituents fear that they're either losing their job overseas or they could lose it to a robot."

When we suggested that she sounded a lot like Donald Trump, without missing a beat she replied: "No. I think I sound like Barbara Mikulski."

She admits the election results makes it tougher to leave, worried a lot of her work -- on Obamacare and beyond -- may be undone.

"You cannot take a wrecking ball to the very agencies that are designed to help American workers get on their feet," she said.

Still, the first woman to ever chair the powerful Senate Appropriations Committee says that behind the scenes bipartisanship she witnessed and engaged in gives her hope.

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In fact, with her offices already all packed up, our interview took place inside the historic appropriations room on the first floor of the Capitol, where she said she was part of many legislative efforts across the partisan aisle.

Even the way senators sit at the imposing table -- with the chairman and the ranking member sitting side by side in the middle -- is aimed at a goal "not to square off."

"We sit together," she said, standing over the side-by-side name plates of senators from opposing parties.

"This is symbolic and an actual function of civility where side-by-side we bring our members together for thoughtful discussion thoughtful analysis," said Mikulski.

It's that kind of quiet, unsung bipartisan work that she says she will miss.

"What I won't miss is the crazy partisan prickliness, and this loss of civility, and the fact that we don't take the time to listen to our constituents or to listen to each other. And how we can solve problems in a practical, affordable kind of way?" she said.

The 4' 11" tall senator, first elected to the House in 1976 and then the Senate in 1986, made a long career out of people underestimating her.

"I bring my own stool to have a longitudinal parity. It's not easy to be 4'11" in an institution like this," she quipped.

She has a reputation for churning out quotable nuggets like that, but also for being intimidating at times -- making male colleagues cower, which she is quick to dismiss.

"I've heard of this one before. And I think that when women are persistent and insistent we're viewed as tough. Now, I view it as just being effective," she said.

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She should know about persistence. She recalls one of her first legislative fights early in her career for parity for women when it came to medical research.

"We got money for a famous hormone study that changed medical practice and has reduced breast cancer rates by 15% of the strength," she said.

One of her proudest achievements was shepherding through the Senate the so-called Lilly Ledbetter legislation, aimed at giving women equal pay for equal work. It was the first bill enacted into law by the first black president, and he gave her the first pen he used to sign it. Now, it's the end of the Obama AND the Mikulski eras.

As the trailblazing senator walked out the door dropping pearls of wisdom, she did something rarely seen in public: She choked up remembering the evening of 9/11, when lawmakers came together to sing "God Bless America" on the Capitol steps.

"Regardless of who is president, we need to be able to stand on those steps and sing 'God Bless America' and feel the people in this Congress to come together and put the national interests above any party interest. We take an oath to the Constitution. I've never took an oath to the Democratic Party. I'm a strong Democrat but I believe in a credible country first, and always listen to the people," said Mikulski, ever and always the granddaughter Polish immigrants, and daughter of a working-class grocer. "They really do have the best ideas."