There is only one judicial system in the United States that has adopted some version of the Code of Judicial Conduct: United States Supreme Court, "which has steadfastly resisted promulgating any rules of ethics." For this reason, a bill has been introduced to require the Supreme Court to adopt written ethics rules, but which does not specify the content of the rules, leaving that to the Court itself. The proposed bill, which is very short, can be found here.
Prof. Steve Lubet (Northwestern) has posted a comment on the act in both The Faculty Lounge and the Legal Ethics Forum. The post is the same but each blog has its own discussion in the comments section.