Retirement, with continuance of pay for themselves, provision for dependents and pay during temporary disability, and the encouragement of long tenure in police service of paid policemen becoming aged or disabled in the service of the state or any of its cities, is hereby declared to be a public purpose of joint concern to the state and each of its cities in the protection of lives and conservation of property and essential to the maintenance of competent and efficient personnel in police service.
Idaho Code § 50-1501