Some states provide criminal penalties for falsely holding oneself out to the public as a lawyer, and the unauthorized practice of law by a non-lawyer.
A person who has a professional law degree but is not admitted to a state bar is not a lawyer, and cannot legally engage in the practice of law. In most states, even the practice of law by an "out-of-state" lawyer is considered the unauthorized practice of law within that state. Exceptions are sometimes made when the out-of-state lawyer is permitted temporarily to practice within the state pro hac vice or in some cases as in-house counsel for corporations.
In addition, a few areas of law, such as patent law, are mandated by the U.S. Constitution to be strictly under federal jurisdiction. In this case, state courts and bar associations are not allowed to restrict the practice of that field of law, and a patent attorney may freely advise clients as to patent matters anywhere in the jurisdiction of the United States, without regard to state court or bar association rules. Furthermore, prior to November 15, 1938, individuals could become registered as “patent attorneys” with the PTO without ever passing a state bar exam or going to law school. That status was grandfathered for patent attorneys registered prior to that date. This represents a holdover to the traditional meaning of the term “attorney” as “agent” or “attorney-in-fact”. There are still some living patent attorneys who became registered as patent attorneys before that date, as far back as 1934. Today, a non-lawyer who takes and passes the patent bar would be considered a patent agent.
In some jurisdictions, the definition of the practice of law is quite strict. Persons have been successfully prosecuted for publishing do-it-yourself will forms and for representing special education children in federal proceedings as specifically allowed by federal law.
Paradoxically, some jurisdictions will allow a non-attorney to sit as a judge, usually in lower courts or in hearings by governmental agencies, even though a non-attorney may not practice before these same courts. Similarly, in a jurisdiction where a judge is elected by the people, the judge often need to be licensed to practice law or trained in any particular way. Likewise, the U.S. Constitution does not provide any such requirement for a U.S. Supreme Court justice or other federal judge, although no non-lawyer has ever been appointed as a federal judge