SEIU president Andy Stern did the unusual yesterday and broke some news on Twitter: In Twitter-esque shorthand--unnecessary, as the message came in well under the allotted 140 characters--Stern wrote, "Congressman Sestak impressive on CNN. Visiting him tomorrow."

We'll try to learn more about the meeting once it's all said and done. Keep in mind, though, that it comes a day after Sen. Arlen Specter (D-PA) insisted on Meet the Press that he's not a loyal Democrat, and opposes significant aspects of the President's agenda. That outburst (unsurprisingly) hasn't done much to quiet calls from the left for Sestak to challenge Specter in the Democratic primary next year.