ABA ethics opinions are written by the Standing Committee on Ethics and Professional Responsibility. These opinions are advisory, and not binding on any court. Formal opinions are on matters deemed to be of interest to a large number of attorneys.
ABA informal opinions are on topics that are not of wide interest. Informal opinions have not been issued since 1989.
Unlike bar association ethics opinions, case law on legal ethics is binding on the jurisdiction where the case has been decided. Ethics case law may cover a wide variety of issues, including legal malpractice or the imposition of sanctions under the rules of civil procedure. There are several ways to find legal ethics case law, including:
Digests: Legal ethics case law may be found in the West digest system under the topic "Attorney and Client" and under subheadings such as "Disbarment," "Discipline," or "Licenses."
American Law Reports (ALR): includes annotations on legal ethics and lawyer disciplinary actions.
Shepard's Professional and Judicial Conduct Citations: provides citations to cases dealing with provisions of the Model Rules.