Democratic U.S. Sen. Christopher Dodd, a 30-year incumbent who has been struggling in public opinion polls for more than a year, announced today he will not seek re-election, while Attorney General Richard Blumenthal said he will seek the seat.

Dodd made the announcement in an eight-minute speech outside his home in East Haddam.

He expressed his "deepest gratitude to the people of Connecticut for the remarkable privilege of being elected eight times over the past four decades to our national assembly," he said. "You have honored me beyond words with your confidence.

Dodd talked about multiple reasons and personal events in his life that prompted him to decide against seeking re-election. For nearly a year, Dodd has been trailing in the polls to Republican front-runner Rob Simmons, but the year has been tumultuous in Dodd's personal life.

After facing the death of his sister in July, Dodd suffered the blow of the death of his close friend, Sen. Ted Kennedy, in August. He also faced prostate cancer surgery in August and took off much of the month from the campaign trail.

Still, he continued working at a high-speed pace in Washington, D.C., on health care reform and other bills.

"I love my job as your senator,'' Dodd said. "I always have -- still do.''

He acknowledged that his poll numbers had placed him in "the toughest political shape of my career.'' But Dodd said it would be "absurd'' to predict so far in advance of the November election whether he would win or lose. Despite being behind in the polls, Dodd's campaign always maintained that he could pull off a come-from-behind victory.

"None of us is irreplaceable,'' Dodd said. "None of us is indispensable.''

Since making the decision not to run, "he's been in a great mood,'' said a source close to the campaign who requested anonymity. "A weight's off his shoulder and he's happy."

Dodd views the recently-passed healthcare bill as a crowning achievement, the source said.

"He went to Teddy's gravesite and spent time there after the vote ... that was kind of a turning point.'' Teddy refers to the late Sen. Edward M. Kennedy.

His expected departure will shake up the state's political landscape. Among other things, it eases the way for a run by Blumenthal, who plans to announce for the seat later today. Blumenthal has long expressed a desire to serve in the U.S. Senate but has said he would never challenge Dodd, whom he considers a friend.

Blumenthal is "uniquely suited to step into this campaign, win this race, and represent the people of Connecticut in Washington, D.C., as we continue to confront unprecedented challenges,'' said Roy Occhiogrosso, a Democratic consultant. "The Republicans thought they might steal this seat. Not anymore."

For most of his long political career, Dodd enjoyed strong support and only token opposition. He was long at the center of a number of important battles and landmark legislation, including the Family and Medical Leave Act, which allows workers to take unpaid time off to care for a new baby or a sick relative.

"He has been an extraordinary champion for many causes, but none less then his dedication to children and children's issues,'' said Jonathan Pelto, a former state Democratic Party chairman who once interned for Dodd.

But Dodd's public approval ratings began slipping when he embarked on a long-shot run for president in 2008. His decision to move his family to Iowa, where he was competing in the caucus, annoyed many Connecticut residents.

His political problems were later compounded by revelations that he had received a VIP loan from Countrywide Financial, a now-defunct subprime lender.

The Senate Ethics Committee later cleared Dodd, saying it found "no credible evidence" that he received any special favors or discounts, but the damage had been done. Questions about the purchase of a cottage in Ireland and his role in the AIG bonus fiasco also hurt him, as did simply being chairman of the Senate Banking Committee while the economy was melting down.

His yearlong burst of advocacy on a myriad of issues, from reforming the financial regulatory system to taking on credit card companies to overhauling health care in America, wasn't enough: a Quinnipiac University poll in November shows that more than a quarter of the Democrats surveyed disapprove of the way Dodd is handling his job as U.S. senator, even though they overwhelmingly back the causes he has taken on. Among unaffiliated voters, his disapproval rating was 60 percent.

He was also facing a bruising and potentially very expensive re-election campaign -- Rob Simmons, a former congressman, and multimillionaire Linda McMahon, former CEO of the World Wrestling Entertainment, broker and author Peter Schiff are his Republican opponents. Democrat Merrick Alpert and independent candidate John Mertens are also running.

In addition to his political troubles, it has also been a personal challenging year for Dodd, who is 65 and the father of two young children. He lost the man he described as his best friend in the Senate, Massachusetts Sen. Edward M. Kennedy, to brain cancer in August. And also over the summer, Dodd disclosed that he was being treated for prostate cancer.

Gov. M. Jodi Rell said the state will miss Dodd's leadership.

"I thank Senator Dodd for his more than 30 years of work on behalf of the people of Connecticut, who have benefited tremendously from his dedication and devotion to public service," she said in a statement. "Throughout his years in the House and Senate, he has had the interests of Connecticut foremost in his mind."

U.S. Rep. John Barry Larson said Dodd has been a giant in Connecticut politics, and his 30 years in the U.S. Senate cannot replaced overnight.

"It's an enormous loss for the state of Connecticut,'' said Larson, who said he will not run for Dodd's seat. "His extraordinary service is only superseded by his acumen and understanding of the process, his ability to work across the aisle. It's not replaceable."

Regarding the tough race that Dodd would have faced in 2010, Larson said, "I think he would've won the election."

Larson said he believed that the recent death of Dodd's sister, the death of Ted Kennedy, and Dodd's own surgery during the summer influenced Dodd's decision to retire. But he said Dodd is still focused on getting the Senate and House health care reform bills combined so that they can go to President Barack Obama's desk and called him "a happy warrior."

Larson seemed like the news weighed on him, and said it was hard for him to think of Dodd leaving Congress as "someone who worked for him," and who served as his campaign coordinator in the 1st District in 1980.

When asked if he was excited about Blumenthal's entry into the race, Larson said, "Dick certainly is a very qualified and capable guy."

Main Street in East Haddam, lined with historic houses and a view of the Connecticut River, was a parking lot of TV satellite trucks before Dodd's speech. State police directed cars into the one lane not occupied by media vehicles.

More than an hour before the noon announcement, an events company went to work transforming the 1854 home -- a onetime schoolhouse -- into a media pen. A row of tripods lined a platform set up just inside the white fence, speakers stood posted by the bushes outside the front windows and a podium stood on a platform just beyond the front steps of Dodd's white house. Every once in a while, a staffer swept snow off the stage where the senator would speak.

A handful of neighbors joined the gaggle of reporters, photographers, personalities and supporters who filled the snow-covered lawn. Carl Viggiani, a retired Wesleyan professor who lives down the road, watched from the second row as his longtime neighbor announced he wouldn't seek another term in the Senate.

"I'm desperately unhappy that he's leaving," Viggiani said, bundled in a red plaid jacket, wool gloves and a pair of heavy boots nearly up to his knees. "He's a good man, a great senator, and they just published a lot of dirt about him that wasn't true."

Viggiani said he hoped Dodd is in good health.

"He may not think it's worth the fight for the next nine months," Viggiani said.

He watched as Dodd's extended family and friends exited the house and took up perches on the front steps. Viggiani announced each person by name, noting that Dodd's brother Nick "looks just like him" and remarking on the "magnificent shock of white hair" the Dodd men shared.

Shortly before the press conference began, two neighbors stood across the street, looking down at the row of news trucks. One held a camera inside the front of her coat. They planned to watch the press conference and called Dodd a good neighbor with a lovely family. Both women declined to give their names.

Asked for their thoughts on the scene outside her home, one of them said, "I guess it'll be the last time."