A justice of the supreme court shall be a citizen of the United States and of the state, a resident of the state for five years immediately preceding appointment, have been engaged for not less than eight years immediately preceding appointment in the active practice of law, and at the time of appointment be licensed to practice law in the state. The active practice of law includes
(1) sitting as a judge in a state or territorial court;
(2) being actually engaged in advising and representing clients in matters of law;
(3) rendering legal services to an agency, branch, or department of a civil government within the United States or a state or territory of the United States, in an elective, appointive, or employed capacity;
(4) serving as a professor, associate professor, or assistant professor in a law school accredited by the American Bar Association.