AP Sources: Democratic Sen. Ben Nelson to retire

AP Photo/Susan Walsh, File

In this file Feb. 11, 2009 file

photo, Sen. Ben Nelson, D-Neb. talks to reporters on Capitol Hill in

Washington. Sources say Nelson will retire.

LINCOLN, Neb. — Sen. Ben Nelson of Nebraska plans to retire rather than seek a third term, two people with knowledge of the decision said Tuesday, a significant setback for Democratic efforts to maintain control of the chamber next year.

The people with direct knowledge of Nelson's decision told The Associated Press that the 70-year-old conservative Democrat will announce his plans Tuesday. They spoke on condition of anonymity because Nelson had not yet made the announcement.

Republicans, who need to net four seats to take back the Senate in 2012, have heavily targeted Nelson's seat. They say Nebraska has tilted further to the right in recent years and think Nelson's vote for President Barack Obama's signature health care legislation would have weighed him down, noting he dipped in polls after the health care debate.

Nelson still would have given Democrats a fighting chance. A two-term governor before winning a Senate seat, he has shown an ability to rebound after being down in statewide races before.

But he recently has expressed frustration with the divided Congress' inability to pass meaningful legislation and told the AP last month that he would make a decision over the holiday season. He meanwhile piled up campaign cash, hired a campaign manager and watched his party spend more than $1 million on ads supporting him.

The preparation had left him with a healthy cash advantage. He had more than $3 million cash on hand last month, about twice his nearest competitor, and had the luxury of stockpiling money while Republicans focused on a crowded primary that includes Don Stenberg, the state's treasurer, Jon Bruning, the attorney general, Deb Fischer, a state senator, and Pat Flynn, an investment adviser.

Nelson was first elected to the Senate in 2000, defeating Republican contender Stenberg to replace the retired Bob Kerrey. He has considered himself a centrist since, often supporting what are usually considered Republican ideologies of less government, lower taxes and fiscal restraint.

He was one of only two Senate Democrats to side with Republicans earlier this year on a failed GOP bid to block new federal controls on power plant pollution that blows downwind into other states. He took great pride in his membership in the 2005 "Gang of 14," made up of Republicans and Democrats who brokered a deal to avoid a filibuster showdown over President George W. Bush's judicial nominees.

Nelson upset incumbent Nebraska Gov. Kay Orr in 1990 to earn his first statewide office and was re-elected in 1994 by a landslide. In 1996, he reneged on a campaign pledge that he would not seek higher office while governor and announced his candidacy for the Senate seat vacated by the retiring Gov. Jim Exon.

Omaha millionaire businessman Chuck Hagel soundly defeated Nelson in that Senate race. The two later served as colleagues when Nelson was elected in 2000.