Senator Jeff Bingaman of New Mexico, a fifth-term Democrat and chairman of the Energy and Natural Resources Committee, said he won’t seek re-election next year.
Bingaman, 67, becomes the fourth member of the Democratic Senate caucus to decide not to face voters in 2012, enhancing Republican prospects to seize control. Democrats have a 53-47 majority.
Bingaman said in a statement that serving in the Senate has been a “great honor and a great responsibility,” yet he and his family want to return to his home state after what they viewed as a temporary move to Washington years ago.
“At the end of this term, we will come home to New Mexico to live, and to pursue other challenges,” he said.
His seat will be tough for Democrats to defend, said Jennifer Duffy, Senate editor of the nonpartisan Cook Political Report.
“Democrats now have four open seats, and three of them are in the tossup column,” she said. “The cards are lining up in a way that makes it increasingly possible that Republicans can take a majority.”
The Democrats’ Senate majority includes two independents who vote with them. One of them, Joe Lieberman of Connecticut, has said he won’t run in 2012.
Other Democrats who have announced retirement plans are Jim Webb of Virginia and Kent Conrad of North Dakota. On the Republican side, Senators Kay Bailey Hutchison of Texas and Jon Kyl of Arizona, the second-ranking Republican leader, have said they will leave the Senate after next year.
Bingaman’s chairmanship put him at the forefront of debates over energy legislation, including a comprehensive measure that passed in 2007.
When energy legislation was blocked in the last session of Congress, he tried unsuccessfully to push through a smaller measure to require utilities to generate a minimum share of their electricity from renewable sources like wind and solar energy.
Bingaman favors more domestic oil drilling and some expansion of nuclear power, putting himself at odds with many other Democrats and with environmental groups.
A member of the Senate Finance Committee, he was one of six senators who participated in bipartisan talks in 2009 to craft a health-care overhaul. Three Republicans in the talks ultimately opposed the measure, though the concepts that came from the talks helped shape the legislation signed into law by President Barack Obama last year.
Former Attorney General
A former New Mexico attorney general, Bingaman won his last Senate election in 2006 with 71 percent of the vote. Duffy said possible Republican contenders for the seat include former U.S. Representative Heather Wilson, Representative Steve Pearce and former Governor Gary Johnson. On the Democratic side, Representatives Martin Heinrich and Ben Lujan are possible candidates, she said.
New Mexico favored Obama in 2008, giving him 57 percent of its vote over Republican presidential nominee John McCain. Still, the state often narrowly splits between the parties, with Republican President George W. Bush winning the state in 2004 by about 6,500 votes. In 2000, Democratic presidential nominee Al Gore carried the state by fewer than 400 votes.
In November, voters elected a Republican governor, Susana Martinez, as New Mexico’s first female chief executive.