NBC's First Read has confirmed, per a high-ranking Democratic source, that Nebraska Sen. Ben Nelson (D) will NOT seek re-election in 2012.
The conservative Nelson, who often voted with Republicans "will be the least missed member of the Democratic caucus next year," said that same high-ranking Democratic source.
While Nelson may have often voted with Republicans, his decision not to run comes as a blow to Democrats' hopes of maintaining control of the Senate, unless Democrats find a top-notch recruit like former Nebraska Sen. Bob Kerrey (D), who is reportedly considering a run with Nelson's seat open.
**UPDATE** from AP (3:27 p.m. EST): Democratic Sen. Ben Nelson tells supporters he'll retire: "Simply put: It is time to move on"