American attorneys are regulated at the state level. State Bar membership is mandatory in some jurisdictions and voluntary in others. Regulation of the legal profession is carried out through a state regulatory agency, a discipline commission, or a discipline committee. In many states, lawyer discipline is the responsibility of the state's court system rather than the bar association.
Resources:
ABA Directory of Disciplinary Agencies (October 2018)
Regulation of the Legal Profession in the United States: Overview (April 2018)