They can to the extent they not say a thing about their personal views, only their legal views and keep to the "new tradition" set by Roberts that personal views have no room on the Supreme Court.
As he said, this is why they all wear Black Robes.
I think a person of Judge Roberts intellect and character comes along only once or maybe twice in a lifetime.
His intellect is so far beyond the average to be incomprehensible to me.
I think Stephen Hawkins in the science field would be comparable in intellect, but of course in science, not law.