I think you're wrong twice.
I don't think tax policy is a social issue. I think it's fiscal, and i think it is one of the large watershed distinctions between country-club conservatives and social conservatives.
I also don't think that the two Senators you mention are on board with judicial nominations -- Collins and Specter. I know that they DID vote to confirm the two most recent Justices. But I REMEMBER lots of other nominees, and I REMEMBER Specter's opposition -- Bork is the classic, but there's others.
I also think that RINO support of Specter, while leaving Santorum out to dry, is classic.
RINOs are Just as bad as libs when it comes to social conservatives.