To be eligible for any statewide elective office, a person, by the date of his qualification as a candidate, shall have attained the age of twenty-five years, be an elector, and have been a citizen of the United States and of this state for at least the preceding five years. In addition, the attorney general shall have been admitted to the practice of law in the state for at least the five years preceding his election. During his tenure in office, a statewide elected official shall hold no other public office except by virtue of his elected office.