WASHINGTON (Reuters) - Senator Olympia Snowe, one of the few remaining Republican moderates in Congress, stunned both parties on Tuesday by announcing she will not seek re-election for a fourth six-year term in November, complaining of partisan gridlock.
The Maine senator's decision was all the more surprising because of her strong re-election prospects. It complicates the Republican effort to wrest control of the Senate from President Barack Obama's Democrats in November elections.
Snowe said both parties are to blame for the gridlock that has plagued Congress and she expected no short-term improvement despite public disapproval ratings near 90 percent.
"I think people are shocked by the Senate not being able to come together and to come up with solutions to the big problems," Snowe told Reuters outside her Senate office.
"We're wasting precious time. We could have done some big things. We could have had an energy policy. We could have had tax reform. We could have had regulatory reform."
She urged Americans to "expect and demand" an end to gridlock from their elected officials.
Snowe, 65, said she was in good health and had "no doubt" she would have won re-election in November. She said she was "well prepared for the electoral battle" she would have faced, one that analysts think could have come from the conservative wing of her own party as well as from Democrats.
"She wasn't facing a difficult race and had raised plenty of money," said Jennifer Duffy of the Cook Political Report, which tracks political races. Duffy said Snowe's decision was "more than a surprise. It is a shock."
Two Democrats, former Maine secretary of state Matt Dunlap and Jon Hinck, a member of the state legislature, are seeking their party's nomination to run for the Senate seat.
With Snowe out of the running other Democrats are expected to jump in before the March 15 filing deadline.
Among Republicans, recent polling suggested Snowe could be endangered by a more conservative primary challenger, but few had emerged.
"Maine is now a top pickup opportunity for Senate Democrats. If there is one place in the country that is likely to reject the extreme, anti-middle class, divisive Republican agenda it is Maine," said Guy Cecil, executive director of the Senate Democratic campaign committee.
Democrats control the Senate with a majority of 53 seats to 47. Republicans need a net a gain of four seats to take over the 100-member chamber. But if a Republican wins the White House in November they would need just three seats since the vice president, as Senate president, would break a 50-50 tie and give his party control.
Maine voted for Obama in the 2008 election by a 17-point margin.
Obama lauded Snowe's efforts to work across the deep party divide. "Senator Snowe's career demonstrates how much can be accomplished when leaders from both parties come together to do the right thing for the American people," Obama said in a statement.
Maine's junior U.S. senator, Susan Collins, another moderate Republican, said she was "devastated" by Snowe's decision, saying she "defines public service at the highest level."
"Olympia could always be counted on as a leader who sought solutions, not political advantage," Collins said.
Senate Republican leader Mitch McConnell called Snowe "a tireless advocate for the people of Maine, our nation's military, and small businesses across the country."
Snowe racked up many firsts during a legislative career that included stints in Maine's House and Senate and eight terms in the U.S. House of Representatives before she was elected to the U.S. Senate in 1994.
The first Greek-American woman to serve in the House and Senate, the hard-working legislator has rarely missed a roll call vote in her career.
Snowe was listed by Time magazine as one of America's 10 best senators in 2006. She was cited for effective work on behalf of Maine's residents and the ability to set aside partisanship. That year, she won re-election in a 74 percent to 21 percent landslide.
In 2009, Snowe angered many in her party by being the only Republican to vote for Obama's signature healthcare reform bill in the Senate Finance Committee, saying she believed the process should move forward. However, she voted against the bill when it came before the full Senate.
Over the years conservative groups, appalled by Snowe's support of legalized abortion, environmental protections, stem cell research and gay rights, have branded her a "RINO" -- a Republican in Name Only.
Both Snowe and Collins regularly cross the aisle to vote with Democats. Snowe voted in favor of the 2010 Dodd-Frank financial regulation bill, saying the legislation would protect Americans from "greedy and reckless Wall Street practices."
Snowe, whose father came to the United States from Sparta, Greece, has a personal history marked by tragedy that seems to echo her heritage.
Both parents had died by the time Olympia was 10 - her mother of breast cancer, her father of heart disease. Orphaned, she moved to Auburn, Maine, from her home town of Augusta to be raised by an aunt and uncle.
In 1973 Snowe's first husband, Republican state legislator Peter Snowe, was killed in a car crash. She is now married to John McKernan, a former governor of Maine, and lives in Falmouth, near Portland.
As described by Snowe, being a moderate Republican had become increasingly hard at a time when the two parties in Congress have engaged in endless bickering over nearly every issue being debated - from deficit-reduction to energy policy and tax cuts.
"It's is true that being a Republican moderate sometimes feels like being a cast member of Survivor," she told The New York Times in 2009. "You are presented with multiple challenges, and you often get the distinct feeling you're no longer welcome in the tribe."
Writing by Ros Krasny; Additional reporting by Richard Cowan. Editing by Mary Milliken and Christopher Wilson