Greg Sargent’s take on Arlen Specter’s Meet the Press denial that he had promised President Obama that he would be a “loyal Democrat” is a spot-on analysis of what Democrats need to take away from this first week with Arlen and how his behavior relates to their need to manage a successful agenda.

So Specter wants us to believe that this story is false — even though he and his office stayed quiet about it and didn’t dispute it for a full five days after it appeared. If Specter privately fibbed to Obama in vowing loyalty to him and the Dems, and is now publicly fibbing about having ever said this, it seems like something Dems might want to keep in mind about their newly-minted Senator.

Specter will be a useful member of the Democratic caucus insofar as he deems it politically expedient for him to be a “loyal Democrat,” regardless of promises to the President.  This obviously isn’t a problem limited to Specter, but what we also see from conservative Democrats like Lincoln, Landrieu, Ben Nelson, and a couple others. Managing these Senators will almost certainly determine how successful the Obama agenda is in the early going.

Personally I think these people should be put on a short leash and threatened electorally by the party institution if they stand in the way of the agenda the American public overwhelmingly voted to put in place last November. But I’m just a DFH…