The only reason the above voted against Roberts was because they believed him to lack a (in their view) vital ingredient in a Supreme Court Justice - a progressive stance.
Read 'Men in Black' by Mark Levin, definently skip the forward, but it should provide an interesting yet basic explorative in to the history of the Supreme Court.
Robert Bork's ~1996 book "Slouching Towards Gommorrah" is another interesting view on the lack of originalism within the court as it's history has shown (Bork also made a great speech on C-Span in regards to Robert's senate hearings which basically went over the basic points in his book).
I'm still making up my mind on the issue, progressivisim or originalism?
Normally I'd say orginalistic candidates would be best suited for the U.S. Supreme Court, but with increasing federalism coming from the executive branch with it's executive orders and apathy coming from the American people combined with corruption from our representatives, I may have to look forward to only welcoming so-called progressive or even activist judges simply to keep balance in the U.S. .