Republican Scott Brown won Tuesday’s special election for the late Democrat Ted Kennedy’s seat.

Brown’s win not only signaled a major upset in liberal Massachusetts, it also left President Barack Obama’s health care overhaul in doubt, and cast a shadow over his first year in office.

Brown’s victory over Martha Coakley stripped Democrats of the 60-seat Senate supermajority needed to overcome GOP filibusters against future Senate action on a broad range of White House priorities, CNN reported. Senate Democrats needed all 60 votes in their caucus to pass the health care bill.

Democrats indicated they would allow Brown to be seated as soon as possible, deflating a budding controversy over whether they would try to block him long enough to complete congressional passage of the health care plan he has promised to oppose, according to The Associated Press.

“The people of Massachusetts have spoken. We welcome Scott Brown to the Senate and will move to seat him as soon as the proper paperwork has been received,” Senate Majority Leader Harry Reid, D-Nev. said, according to The AP.

Massachusetts Secretary of State William Galvin said he would notify the Senate on Wednesday that Brown had been elected.

Brown’s victory made real the once unthinkable prospect of a Republican filling the seat held by Kennedy, known as the liberal lion, for almost 47 years until his death from brain cancer in August.

Pictured above is Scott Brown.