WASHINGTON (3/25/13, UPDATED 3:30 p.m. ET)--Sen. Tim Johnson (D-S.D.) will make an announcement tomorrow that he will not seek re-election, according reports, including an early one today from Reuters, which cited unnamed sources.
The report said Johnson, who is 66 and has served in the Senate for more than 15 years, has been expected to retire after his current term that will end in 2014.
Other reports say Johnson will make his announcement at 4 p.m. (ET) tomorrow at a press conference at the University of South Dakota, his alma mater.