Senate Banking Committee Chairman Tim Johnson (D-S.D.) is expected to announce today that he will retire at the end of his term in 2014. Johnson, who has chaired the banking panel since 2011, would be the fifth Senate Democrat to not seek re-election. Sens. Carl Levin of Michigan, Tom Harkin of Iowa, Jay Rockefeller of West Virginia and Frank Lautenberg of New Jersey have also announced they won't run for re-election in 2014.
Democrats in South Dakota have already begun discussing a possible successors to Johnson, including Sen. Johnson's son Brendan, South Dakota's U.S. attorney.
Learn more about Sen. Tim Johnson.