More from Jake Tapper at ABC News:
At 10:25 am, in the Oval Office for his Economic Daily Briefing, President Obama was handed a note.
“Specter is announcing he is changing parties," it read, a reference to Sen. Arlen Specter, R-Penn.
Seven minutes later the president was on the phone with Specter.
“You have my full support," the President said, adding that he was "thrilled to have you.” . . .
There's some pragmatic politics at place here as well. Facing a grueling primary challenge against former Rep. Pat Toomey, R-Penn. -- who almost defeated Specter in the GOP primary in 2004 -- Specter could well have lost to Toomey this time. In a Quinnipiac poll last month among registered Pennsylvania Republicans, Specter trailed Toomey 27-41 percent. That poll showed that Specter had a 29 percent favorability rating among Republicans, compared with 60 percent among Democrats. . . .
Last month, the irrepressible Gov. Ed Rendell told a Pennsylvania cable channel that he, Sen. Bob Casey, D-Penn., and Vice President Biden from neighboring Delaware have all been lobbying Specter to switch.
"We've tried," said Rendell. "Myself, Senator Casey, Vice President Biden have tried to talk him into it, but he's bound and determined to stay a Republican," Rendell said. "He doesn't want to see Republican moderates banished from the earth."Asked what would happen if Specter ran as a Democrat, Rendell said, "he'd be unopposed" in the primary and "he'd win 60-65 percent of the vote in the general election."