In modern practice lawyers frequently act outside the territorial limits of the jurisdiction in which they are licensed to practice, either in another state or outside the United States. In doing so, they remain subject to the governing authority of the jurisdiction in which they are licensed to practice. If their activity in another jurisdiction is substantial and continuous, it may constitute practice of law in that jurisdiction. See Rule 5.5. If the rules of professional conduct in the two jurisdictions differ, principles of conflict of laws may apply.
Similar problems can arise when a lawyer is licensed to practice in more than one jurisdiction.
Where the lawyer is licensed to practice law in two jurisdictions which impose conflicting obligations, applicable rules of choice of law may govern the situation. A related problem arises with respect to practice before a federal tribunal, where the general authority of the states to regulate the practice of law must be reconciled with such authority as federal tribunals may have to regulate practice before them.