“As the first Democratic woman elected to the Senate in my own right, I am honored to join Senator Clinton in this historic effort to break the last barrier for women in public life,” Mikulski said.

Mikulski cited Clinton’s attention to women’s rights as one of the main reasons why she chose to endorse the presidential hopeful.

“I am truly honored to have the support of Barbara Mikulski,” Clinton said. “She has literally paved the way for me and countless other women who now serve in the Congress, and she’s never forgotten who she represents.”