BOSTON, Massachusetts -- Republicans have won a stunning upset in Massachusetts' Senate election, dealing a potentially fatal blow to US President Barack Obama's health care reforms.
Republican Scott Brown pulled off the surprise victory on Tuesday, capturing the late Democratic icon Edward Kennedy's seat in a stern rebuke of Obama exactly a year after he swept into office.
With more than 80 percent of the vote in, Brown had an invincible lead of five percent over his Democratic rival Martha Coakley, CNN and MSNBC reported.
Coakley originally expected a cakewalk in a historically left-leaning state, but Brown's populist challenge to Democratic rule in Washington turned the race into an unstoppable insurgency.
"I wish we were here with other and better news tonight, but we are not," Coakley told supporters in a concession speech shortly after speaking with Brown.
"I have offered him my congratulations," she said.
Coakley's loss strips Democrats of their 60th vote in the Senate, and with that the end to the supermajority allowing them to override Republican blocking in the upper house on the Obama agenda.
The first big victim, analysts say, is likely to be Obama's health care reforms package, which has been struggling to pass in Congress even with the Democrats' hefty majority.
Brown, who will become the 41st Republican in the Senate, has promised to vote against health care, thereby derailing the bill.
"I think you can make a pretty good argument that health care might be dead," Democratic congressman Anthony Weiner told MSNBC television.
The White House admitted Obama, who rushed to campaign alongside Coakley on Sunday, was "surprised and frustrated" and "not pleased" about the race. But the administration denied the election showed he was out of touch with the angry mood felt by Americans.
Analysts point to a lackluster campaign by Coakley and a misreading by the Democrats of popular anger at Washington in time of recession and at what Republicans say is an over-expanding government.
Beyond health care, a Brown triumph will have wider implications for Obama's agenda and political prestige, and complicate his bid to pass items like cap-and-trade climate legislation and immigration reform.
A Republican win will also likely scare some conservative Democrats from Obama's side, as they face mid-term congressional polls in November, with the president's approval ratings slipping and the economy in the mire.
"The reality of it is that people of Boston... have a very definite idea of what they want and what they don't want," Republican National Committee Chairman Michael Steele told CBS.
The White House has been arguing that the Massachusetts vote is not a referendum on Obama, pointing out he still enjoys high approval in the state.
They also reject the idea voters are out to thwart his bid to rein in health insurance companies, cut costs and grant health care to 31 of the 36 million Americans currently without coverage.
Obama will nevertheless call the winner of Tuesday's election, his spokesman Robert Gibbs said, and views the race as more evidence of the popular "upset and anger" at incumbent politicians which powered his own 2008 election race.
"That's not a surprise to us in this administration because... in many ways, we're here because of that upset and anger," Gibbs said.
