When it comes to women in politics, Maryland has been a national leader for decades. It was the first state to have a bipartisan women’s legislative caucus, and it ranks seventh nationwide in terms of the portion of women in the state legislature.

Sen. Barbara Mikulski is a large part of the reason for Maryland’s legacy of woman leadership, said Debbie Walsh, director of the Center for American Women and Politics at Rutgers University. A 30-year Senate veteran, Mikulski is known as the “dean” of women in the chamber and a leader on women’s rights.

Mikulski is retiring when her term ends in January, and on Tuesday, Maryland voters elected Democratic U.S. Rep. Chris Van Hollen to fill her seat. The result is Maryland’s first all-male congressional delegation since 1971.

“To think that her state will now not have any representation by women in its congressional delegation is surprising and disappointing,” Walsh said.

Mikulski is one of two women leaving the Maryland congressional delegation in January. U.S. Rep. Donna Edwards gave up her House seat to run for Mikulski’s Senate seat, but lost to Van Hollen in the primary.

During that race, Edwards and her supporters said she was the more logical choice to continue Mikulski’s legacy.

Republican state Del. Kathy Szeliga made the same argument about herself in the general election.

“Women offer a different perspective and lawmaking is all about diverse opinions at the table,” she said on election night. “Look, more than 60 percent of the voters in Maryland are women.”

She said that as a woman, she better understands the needs of working women.

Yet Van Hollen enjoyed the endorsements of Mikulski, Edwards and several women’s groups.

During a debate last month on WAMU radio, he pledged to continue one of Mikulski’s priority issues, equal pay for women.

“I’ve been endorsed by the Women’s Chamber of Commerce, partly because I support the idea that women who work hard should be paid the same as a man who does the same job with the same qualifications,” he said. “I have a daughter, Anna. I hope that she will get equal pay for her equal work.”