What does Sir Robert mean when he says that he wept because "right had been done", "not justice"? How does he define "right" and what means "justice" to him?
This is interesting because Mr. Arthur Winslow says to his wife that he is fighting for "justice".
"SIR ROBERT: I wept today because right had been done.
CATHERINE: Not justice?
SIR ROBERT: No, not justice. Right. Easy to do justice, very hard to do right."
Well, I think when he says "justice" he refers to the legal system and its rules. "Justice" means to him that someone gets a fair trial and is found guilty by a judge on the base of law. When Catherine reproaches him in his office with the fact that Len Rogers committed suicide and that many people believed him innocent, Sir Robert answers: "As it happened, however, he was guilty."
I interprete this sentence as legal positivism: Len Rogers was found guilty by a judge, therefore he was guilty. But actually - the "Winslow Case" shows it - it has a lot to do with money and the skills of your lawyer, if you are found guilty or not. If Arthur Winslow were not prepared to pay such a huge amount of money to contract Sir Robert, they would probably not win the case and Ronnie would be found "guilty".
When in the end Sir Robert says: "No, not justice. Right. Easy to do justice, very hard to do right", I interprete the term "right" as that your conscience tells you is right. And why is it so difficult to do right? Because of corruption and the high price that you pay for not "siding with the great", but defending the right of the powerless against the establishment.
By the way, the fact that he weeps in court because "right had been done" shows that he has not always "done right" before. I do not share the interpretation that Sir Robert is an idealist from the beginning of the film and that Catherine is just too prejudiced to see it. She is not so wrong about him in the beginning. She is wrong when she calls him unfeeling and passionless: "I doubt any emotion at all can stir in that dead heart." It's great fun that it is her of all people who causes quite a stir in it.