Defection coup marks Obama's first 100 days

Barack Obama was today handed the ideal gift to celebrate his 100th day in office as a senior Republican defected to the Democrats.

The President promised to throw his "full support" behind veteran Senator Arlen Specter who stunned US politics by switching sides.

Mr Obama will campaign and raise money for Mr Specter's re-election bid in Pennsylvania next year and is said to be "thrilled" to have him on his side.

The defection adds to the woes of the Republican party after its comprehensive defeat in the election.

Political experts said Mr Specter crossing the floor highlights the disarray the party faces following John McCain's election defeat and the ridiculing of vice-presidential candidate Sarah Palin.

Mr Obama was told about the 79-year-old's defection during an economic briefing. He was handed a note by an aide that read: "Specter is announcing he is changing parties."

The President contacted Mr Specter, one of only three Republicans to support his financial stimulus package, on the phone minutes later and told him: "You have my full support." He added: "We are thrilled to have you." When asked by reporters about the change, he smiled and gave the thumbs up.

The defection comes as the President stages a live televised press conference tonight to mark his 100 days in power.

Mr Specter is considered a moderate and is the 12th most senior politician in the Senate, having held his seat for 29 years. Vice-President Joe Biden, a long time friend of Mr Specter, is known to have had an influence on his decision to change parties after 42 years. Mr Specter called his decision "painful," and said he made it based on public and private polling in Pennsylvania that showed the prospects for winning a Republican primary in Pennsylvania were "bleak".

He said: "As the Republican party has moved farther and farther to the Right, I have found myself increasingly at odds with the Republican philosophy and more in line with the philosophy of the Democratic Party.

"I'm not prepared to have my 29-year record in the United States Senate decided by the Pennsylvania Republican primary. This is a decision that has been reached gradually as I have travelled the state.

"This is a painful decision. I know I'm disappointing many of my colleagues. The disappointment runs in both directions. I'm putting principle at the top of the list."

Republican National Committee Chairman Michael Steele said the move was to further Mr Specter's political interests, adding that the Republican party was looking forward to defeating him next year.

The switch puts Senate Democrats one vote shy of a filibuster-proof majority of 60 seats. They can reach the 60-seat mark if Al Franken holds his current lead in the disputed Minnesota Senate race.