Ramesh, your initial reaction was quite right. You don’t have to be a particular fan of Specter (I’m not) to think that today’s news is bad, to say the least, and, yes, the position in which Specter now finds himself must mean that he shifts (further?) left, taking, in a very real sense, the country with him.
Disastrous.
Sometimes (to borrow Lenin’s phrase), the worse can be better, but sometimes the worse is simply worse.