"It is more important I spend my time and energy trying to solve these problems than to be distracted by a campaign for re-election," the Democratic incumbent, who is chairman of the Senate Budget Committee, said in a statement sent to supporters.
Conrad's departure will put another Democratic Senate seat in jeopardy, following the decision of fellow North Dakota Democrat Sen. Byron Dorgan to not run for re-election last year. Democrats will be defending 23 of the 33 U.S. Senate seats on the ballot next year.
North Dakota Democrats, who are badly outnumbered in the North Dakota Capitol and the Legislature, have no obvious candidate to succeed Conrad. A number of prominent Republicans are likely to be interested in the seat, including Attorney General Wayne Stenehjem.
One Republican, Public Service Commissioner Brian Kalk, said last week he was forming an exploratory committee to test voter support for a campaign against Conrad. Kalk was first elected to the state regulatory board two years ago.
Conrad, 62, said he would serve out his term. He said his priorities during his time left in office are to get the nation's $14 trillion debt under control, reduce the U.S. dependence on foreign energy, address flooding problems in North Dakota's Devils Lake basin and Red River Valley, and write a new five-year farm bill.
"Although I will not seek re-election, my work is not done," Conrad said in his statement. "I will continue to do my level best for both North Dakota and the nation."
Conrad's departure will complete the breakup of North Dakota's formerly all-Democratic congressional delegation.
Former Democratic Sen. Byron Dorgan declined to run for re-election last year and was replaced by former Republican Gov. John Hoeven, who won 76 percent of the vote. North Dakota's only U.S. House member, Rep. Earl Pomeroy, lost a bid for his 10th term to Republican Rick Berg.
Dorgan, Conrad and Pomeroy, who became political allies when Dorgan ran unsuccessfully for the U.S. House in 1974, often advertised themselves as "Team North Dakota" during the 18 years they served together.
Among the state elected officials in the North Dakota Capitol, there is only one Democrat, Wayne Sanstead, the 75-year-old state superintendent of public instruction. Republicans hold two-thirds majorities in both houses of the North Dakota Legislature.
When Dorgan announced last year he would not seek re-election, Democrats endorsed Bismarck state Sen. Tracy Potter, who had never sought statewide office. Democrats had urged Heidi Heitkamp, a former North Dakota attorney general, to seek the job, but she declined; Heitkamp is interested instead in running for governor in 2012.
Potential Republican Senate candidates include Stenehjem, Kalk and Lt. Gov. Drew Wrigley, who took the office in December after Hoeven resigned as governor and Dalrymple, who had been Hoeven's lieutenant governor, ascended to the top job.
Conrad was elected to the Senate in 1986, when he was serving as state tax commissioner. His campaign was waged against a backdrop of low farm prices, and Conrad narrowly defeated Republican incumbent Mark Andrews by hammering him on agriculture issues.
During his first 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.
