WASHINGTON — Outgoing Social Security Commissioner Michael J. Astrue has some parting shots for Congress, the White House and advocates for seniors. They have all "really walked away from Social Security," he says, leaving the program "fraying because of inattention to its problems."

Instead of making the hard choices to fix Social Security's financial problems, policymakers "use it as a tool of political rhetoric," Astrue said.

Astrue, 56, has headed the federal government's largest program since 2007 — he was nominated by former President George W. Bush. By law, Social Security commissioners serve six-year terms, so President Barack Obama will now have the opportunity to choose his own nominee, who must be approved by the Senate. Astrue's last day on the job was Wednesday.