Max Baucus, the powerful Democratic chairman of the U.S. Senate Finance Committee, said on Tuesday he will not seek re-election next year, improving Republican chances of capturing his seat and giving him a freer hand to revamp the tax code.
First elected to the Senate in 1978, Baucus, 71, will become the eighth senator - six Democrats and two Republicans - to announce plans to retire at the end of next year.
"I have decided not to seek re-election in 2014," Baucus said in a statement, saying he will focus for the remainder of his term on improving the tax code, tackling the nation's debt, getting trade agreements approved and other goals.
Democrats now hold the Senate, 55-45. Baucus, of Montana, won a sixth term with 73 percent of the vote in 2008. He had been favored to win a seventh term, but still could have faced a competitive race, according to analysts.
Jennifer Duffy, who tracks Senate races for the nonpartisan Cook Political Report, said she was changing her rating of the 2014 Senate race in Montana from "Lean Democrat" to "toss up."
As Senate Finance chairman, Baucus played a key role in President Barack Obama's landmark overhaul of the U.S. healthcare system, signed into law in 2010.
Baucus is now working closely with his House of Representatives counterpart, Republican Dave Camp, on rewriting the complicated tax code, a project that faces major obstacles from Republicans.
By retiring, Baucus could free himself from the political pressures of running for re-election, but that would not reduce by much the challenges of a tax-code overhaul.
"It may suggest that he is going to devote 100 percent of his energy to tax reform, so that may be a boost for getting it done, because both he and Camp are on the same schedule now," said Ken Kies, a veteran tax lobbyist.
Camp will lose the gavel of the tax-writing House Ways and Means Committee in 2014 under House rules.
Regardless, Kies said, major challenges remain, beginning with Republican opposition to calls by Democrats for tax hikes.
If Democrats retain the Senate in next year's election, Democratic Senator Ron Wyden of Oregon would be next in line in party seniority to replace Baucus as Finance Committee chair.
Baucus is a moderate in a rural state that went for Republican Mitt Romney over Obama in last year's White House race, 55 percent to 42 percent.
Former Montana Democratic Governor Brian Schweitzer is seen as a top contender to run for Baucus' seat, while Representative Steve Daines is among possible Republican candidates.
As a moderate, Baucus often butts heads with more liberal members of Congress, including those in Democratic leadership. He recently opposed the Senate's budget resolution that sought to raise taxes earlier this year and voted against Obama's effort to curb gun violence with new controls on firearms.
The seven senators who earlier announced they would not run for re-election are Democrats Carl Levin of Michigan, Frank Lautenberg of New Jersey, Tom Harkin of Iowa, Tim Johnson of South Dakota and Jay Rockefeller of West Virginia, along with Republicans Saxby Chambliss of Georgia and Mike Johanns of Nebraska.