Nowhere in the rules does it say that you can breach confidentiality because you have a moral objection to your client’s alleged acts. The best you can do is refuse to accept the case at the outset, or withdraw from representation later on. But even that can be highly difficult to accomplish. Maybe your firm represents the client and you have no choice about what cases you’re assigned. Maybe you’re in the midst of trial, settlement talks, or arbitration and a judge won’t let you withdraw because it would do greater harm to your client. You may not have a choice in the matter.