So far he hasnt changed the balance, we are better off on the SCOTUS than we were in 2001 as O Conner was a disaster.
Would you trade to get another Roberts like justice for accepting full Bush type amnesty"? (Would still require a Republican Senate)
No way. However, imagine Eric Holder clones (probably with "moderate" sounding public records) replacing Scalia and Thomas. That would be a huge loss. The left has been planning for this for a long time, and it might be a lot easier than passing amnesty in a bad economy. Do you think the GOP senators have the nerve to filibuster such a nominee?
I don't want amnesty or a leftist SCOTUS, but I know either is possible. All we can do is study the GOP candidates diligently and use our best judgment, taking into account both their positions and probability of being elected.