FILE In this June 21, 1995 file photo, Sen. Barbara Boxer, D-Calif. left, listens as Sen. Edward Kennedy, D-Mass. speaks during news conference on Capitol Hill news conference in Washington, after the Senate voted to end debate on the nomination of Dr. Henry Foster to become surgeon general. Boxer, one of the chamber's most tenacious liberals, announced Thursday she will not seek re-election in 2016 to a fifth term. A staunch supporter of abortion rights, gun control and environmental protections, Boxer has said she is most proud of the vote that she cast against the war in Iraq. From left are, Boxer, Senate Minority Leader Tom Daschle of S.D. and Sen. Paul Simon, D-Ill. (AP Photo/J. Scott Applewhite, File)