WASHINGTON, (Reuters) – U.S. Senator Arlen Specter  abandoned the Republican Party for President Barack Obama’s  Democrats yesterday, putting them within reach of a 60-seat  majority that could give them absolute control of the Senate.

“This is a painful decision,” Specter told reporters of the  stunning decision which boosted his 2010 re-election chances to  a sixth six-year term by sidestepping a tough challenge in the  Republican primary from conservative Pat Toomey.

Senate Majority Leader Harry Reid promptly welcomed  Specter, 79, into the ranks of Democrats, who together with him  now control 59 seats in the 100-member Senate. Democrats will  reach 60 if they hold on to a contested Minnesota Senate race.

A 60-vote majority would be enough to override Republican  procedural hurdles and muscle through key parts of Obama’s      agenda, including measures to provide health insurance to all  Americans and combat global warming while moving the nation  toward energy independence.

The last time either party held 60 Senate seats was in  1978, when the Democrats had 61. Democrat Al Franken, who won  the vote tally in Minnesota, would be the 60th but Republican  incumbent Norm Coleman is challenging the count in court.

“Since my election in 1980 … the Republican Party has  moved far to the right,” Specter said in a statement explaining  his decision. “I now find my political philosophy more in line  with Democrats than Republicans.”

Specter said in the statement posted on his campaign Web  site, “My change in party affiliation does not mean that I will  be a party-line voter any more for the Democrats than I have  been for the Republicans.”  An administration official said Obama was handed a note  during his daily economic briefing at the White House that said  Specter would announce he was changing parties.

A few minutes later, the official said Obama reached  Specter and told him “you have my full support” and that  Democrats were “thrilled to have you.”