This was not quite as significant had it been for the OConner slot. Being that he replaced Rehnquist- and being a Rehnquist disciple- this really isn't going to affect the balance of the Court nor the direction of the Court much.
However, if Roberts turns out to be more of a Stevens or Souter it will be very significant. And also in contrast, if he turns out to be a staunch originalist in the mold of Thomas or a Scalia that too would be significant.
