California Has Adopted The National Standard For Ethics Rules

On May 10, 2018, California's Supreme Court adopted a new set of ethical rules for the state based upon the American Bar Association's Model Rules of Professional Conduct, effective November 1, 2018. A cross-referenced comparison of the new rules to the existing ones is available here.

On that date, every U.S. state will have ethical rules for lawyers that are based upon the Model Rules of Professional Conduct. The dates of adoption are shown here. Puerto Rico is the only substantial U.S. jurisdiction that does not have rules of professional conduct for lawyers based upon the Model Rules. Contrary to my prior coverage of this issue, Maine adopted the Model Rules with select modification in 2009 and there are no longer any states that have ethical rules based upon the prior Model Code of Professional Conduct, which was disavowed by the American Bar Association in favor of the successor Model Rule of Professional Conduct in 1983.

Many states have state specific tweaks to the Model version, and California will have some of its own, but all are based upon the same general framework and starting point language. This gives rise to considerable uniformity between the states in the professional ethics rules that apply to lawyers and to easier comparisons between states when they adopt rules that differ from the Model Rule language. 

Notably, this has been achieved entirely without federal government intervention.