North Dakota U.S. Sen. Kent Conrad said Tuesday he will not seek re-election in 2012 because he wants spend more time working on ways to reduce the nation's $14 trillion debt, which he ranks with a terrorist attack as "the central threat facing the country."
Conrad's departure puts another Democratic Senate seat in jeopardy after the decision of fellow North Dakota Democrat Sen. Byron Dorgan to not run for re-election in 2010. Former Republican Gov. John Hoeven replaced Dorgan in the Senate, winning 76 percent of the vote.
Conrad's announcement came hours before Democratic officials said Connecticut's Sen. Joseph Lieberman also would not seek re-election. Lieberman, one of two Democratic-leaning independents in the Senate, planned to formally announce his decision on Wednesday. The officials spoke on condition of anonymity because they were not authorized to speak publicly.
Democrats now hold a 51-47 Senate edge on Republicans, not including Lieberman and another independent, Vermont's Bernie Sanders. Democrats will be defending 23 of the 33 U.S. Senate seats on the ballot next year.
In an e-mail message to supporters, Conrad said his remaining priorities are to get the national debt under control, reduce U.S. dependence on foreign energy, write a new five-year farm bill and address flooding problems in North Dakota's Devils Lake basin and Red River Valley.
"In thinking about this decision on running again, I just couldn't get past the point that if I'm running for re-election, that's going to take a lot of time and energy away from working on what I think is the central threat facing the country, other than a terrorist threat. And that's the debt threat," Conrad said in an interview with The Associated Press.
He said he had contemplated not seeking re-election for more than a year, saying he had discussed the possibility with Dorgan before Dorgan himself announced in January 2010 that he would not seek re-election.
"I'm a financial person. I've always been concerned about deficits and debt," Conrad, who is the chairman of the Senate Budget Committee, told the AP. "The last thing I want is to look back and evaluate myself and say, 'Boy, you should have done more. You could have done more, you should have done more.'"
President Barack Obama thanked Conrad, saying the North Dakota Democrat had "shown an unmatched dedication to putting our country on a sound fiscal path and commitment to meeting our nation's energy challenges."
Conrad's departure will complete the breakup of North Dakota's formerly all-Democratic congressional delegation.
Dorgan served in the U.S. Senate and House for 30 years before declining to run last year for his fourth Senate term. His successor in the U.S. House, Democrat Earl Pomeroy, lost to Republican Rick Berg last year in a bid for his 10th term.
Dorgan, Conrad and Pomeroy became political allies when Dorgan ran unsuccessfully for the U.S. House in 1974. At the time, Dorgan was state tax commissioner, Conrad was his House campaign manager, and Pomeroy was Dorgan's driver.
The three men often advertised themselves as "Team North Dakota" during the 18 years they served together in Congress, and Conrad said the departures of Dorgan and Pomeroy influenced his decision to step down.
"It's hard to know, honestly, but it had to be a factor," Conrad said. "They are two of my best friends in life."
One North Dakota Republican, Public Service Commissioner Brian Kalk, said last week he was forming an exploratory committee to test support from GOP activists for a campaign against Conrad. Kalk was first elected to the state regulatory board two years ago.
Kalk on Tuesday praised Conrad for his public service and said his departure would not affect his own decision about whether to run. "We will talk with the citizens of North Dakota and with Republicans across the state, and be guided by what is best for our family, our state, and our nation," Kalk said.
Other potential GOP Senate candidates include Attorney General Wayne Stenehjem and Lt. Gov. Drew Wrigley, who took the office in December after Hoeven resigned as governor and Jack Dalrymple, who had been Hoeven's lieutenant governor, ascended to the top job.
Stenehjem, who was re-elected to a new four-year term last year, said he would not rule out a Senate campaign. Wrigley, who is a former North Dakota U.S. attorney and state Republican Party director, declined to speculate about a candidacy, saying North Dakotans should focus on Conrad's public service and leave Senate politics for later.
North Dakota Democrats have no obvious candidate to succeed Conrad. Republicans hold two-thirds majorities in the North Dakota House and Senate, and the party's only statewide officeholder is Wayne Sanstead, 75, the state superintendent of public instruction.
Two Democratic state lawmakers, Fargo Sen. Tim Mathern, 60, and Mayville Rep. Lee Kaldor, 59, have run losing races for governor. State Rep. Corey Mock, D-Grand Forks, gained notice last year with an aggressive _ if unsuccessful _ campaign for secretary of state, but the 25-year-old Mock is short of the U.S. Senate's minimum service age of 30.
Kristin Hedger, 30, a Killdeer businesswoman who ran unsuccessfully for secretary of state in 2006, was promoted as a potential successor to Dorgan last year but decided against the race. She said Tuesday she would be giving a 2012 Senate campaign "a good, hard look."
When Dorgan announced he would leave the Senate, North Dakota Democrats endorsed Tracy Potter, a Bismarck state senator who had never run a statewide campaign, as their favorite to succeed him. He was trounced by Hoeven, getting less than one-quarter of the vote.
When Conrad first ran for the Senate in 1986, his campaign was waged against a backdrop of low farm prices. Conrad narrowly defeated Republican incumbent Mark Andrews in part by hammering him on agriculture issues.
At the start of his campaign, Conrad promised not to seek re-election unless the nation's budget and trade deficits and rising interest rates had been brought under control.
When those goals were not met, Conrad shocked Democrats six years later by announcing he would step down. "The budget deficit is completely out of control," Conrad said in an April 1992 speech on the Senate floor.
However, Conrad ended up making another Senate campaign later that year, when the state's other Democratic senator, Quentin Burdick, died in September 1992. At the urging of North Dakota Democrats, Conrad ran for Burdick's seat and defeated Dalrymple, who was then a state legislator, in a December 1992 special election.
The circumstances led to Conrad's briefly holding both of North Dakota's U.S. Senate seats, after Conrad was elected as Burdick's successor.
Also Tuesday, Republican Sen. Richard Lugar of Indiana announced his plan to seek a seventh term in office. Lugar's spokesman, Mark Helmke, said the senator plans to run a vigorous campaign and that he has already raised more than $320,000.
Associated Press Writer Andrew Miga in Washington, D.C., contributed to this report.