Reporting from Washington — Highlighting the challenge for Democrats in holding the Senate in 2012, Sens. Joe Lieberman (I-Conn.) and Kent Conrad (D-N.D.) are stepping down instead of seeking reelection next year. Their decisions, announced early in the election cycle, will remove two more centrists from an increasingly polarized Senate.
Lieberman, the party's 2000 vice presidential nominee, who now caucuses with Democrats as an independent, will announce Wednesday that he isn't seeking reelection, an aide said Tuesday. Conrad, a deficit hawk, announced earlier in the day that he would retire after 26 years in the Senate.
Their action "clearly makes the Democratic majority shakier," said Stuart Rothenberg, who writes an independent newsletter on congressional elections. Conrad's departure "means the Democratic Party will become more of an East Coast-West Coast party" with fewer lawmakers from heartland states, he added.
Lieberman's decision "enables him for the next two years to be an honest broker between Democrats and Republicans on issues that matter to him — on national security, the debt issue and the environment," said a Lieberman aide who spoke on the condition of anonymity because a formal announcement had not been made.
The Connecticut seat may well go to a Democrat who would be to the left of Lieberman. The 68-year-old senator, first elected in 1988, managed to win a three-way race in 2006 after losing the Democratic primary to a liberal outsider, Ned Lamont, but might have had a tough time winning a fifth term next year.
In North Dakota, Conrad faced a potentially stiff reelection challenge in a state where Republicans took the only House seat and a vacant Senate seat last fall.
Conrad, 62, announced his decision at almost the same time that Sen. Richard G. Lugar (R-Ind.) said he would seek a seventh term despite an expected challenge from the "tea party" movement. Other Republican senators also face the threat of primary opposition in 2012, including Orrin G. Hatch of Utah.
The retirement decisions go to the heart of the 2012 battle over control of the Senate. Democrats and their independent allies have a 53-47 edge, a smaller majority than they had before the GOP won six seats in November. Democrats face a tough road in holding the chamber, because they have 23 seats to defend and the GOP has just 10.
Conrad, chairman of the Senate Budget Committee, is someone Democrats have pointed to when Republicans say they are soft on economic issues.
"After months of consideration, I have decided not to seek reelection in 2012," Conrad wrote in a letter released by his office. "There are serious challenges facing our state and nation, like a $14-trillion debt and America's dependence on foreign oil. It is more important I spend my time and energy trying to solve these problems than to be distracted by a campaign for reelection."
Conrad's decision follows a similar move by former North Dakota Sen. Byron L. Dorgan, one of his best friends, who announced last year he would not seek reelection. Dorgan, a Democrat, was succeeded by a Republican, Sen. John Hoeven, a former governor of North Dakota.
"There are a number of potential Democratic candidates who could make this race competitive, while we expect to see a contentious primary battle on the Republican side," said Sen. Patty Murray, head of the Democratic Senatorial Campaign Committee, in a statement.
President Obama praised Conrad in a statement for his "unmatched dedication to putting our country on a sound fiscal path and a commitment to meeting our nation's energy challenges."
Times staff writer Michael Muskal in Los Angeles contributed to this report.