He already has. There will always be one with four either side. But he defines a middle that is further right than it was under Kennedy and Kennedy was further right than what I think of as the reasonable centre (if we use a linear political model). Or to put it another way, there are too many catholics, chosen because they are catholics, on the bench. And the American catholic legal people seem to hold political views that swing far to the right.
The good news is that at the Supreme Court level, the issue isn't overall so much about integrity. Whereas, obviously, Republican politics is deeply corrupt.