The Washington Post and CNN are both reporting that Sen. Barbara Mikulski (D-MD) will retire at the end of her term. Mikulski is the longest serving female Senator, she was first took office in 1987.
Mikulski has been seen as the Dean of Senate women due to her seniority. Mikulski and the Senate women have often held informal meetings on a regular basis to build relationships, especially bipartisan ones. The bipartisan relationships born out of these meetings have led to compromises across the aisle.
Mikulski became the first female chair of the Senate Appopriations Commitee in 2012. She held the chairmanship until the Democrats lost the Senate majority.
Reports indicate that Mikulski will make the announcement later today in Baltimore, her hometown.