THE TWO GENERAL CATEGORIES OF STATUTES ARE OFFENSE-SPECIFIC STATUTES, AND HABITUAL OFFENDER STATUTES. AS OF 1977, 33 STATES HAD OFFENSE-SPECIFIC STATUTES PROVIDING FOR AT LEAST 20 YEARS IMPRISONMENT WITHOUT THE POSSIBILITY OF PAROLE. MURDER, KIDNAPPING, AND RAPE ARE THE THREE CRIMES MOST OFTEN INCLUDED IN THESE STATUTES. ALL BUT SIX STATES HAVE SOME KIND OF HABITUAL OFFENDER STATUTE. THE MAJOR RATIONALES FOR THE STATUTES ARE SPECIAL DETERRENCE (INTIMIDATION), GENERAL DETERRENCE, INCAPACITATION OF THE OFFENDER, REHABILITATION OF THE OFFENDER, AND RETRIBUTION. OF THESE RATIONALES, ONLY INTIMIDATION AND INCAPACITATION WERE FOUND TO BE SUITABLE FOR EMPIRICAL EXAMINATION. DATA FROM UNIFORM PAROLE REPORTS WERE USED TO ASSESS THESE RATIONALES. DATA ON 29,876 PAROLEES RELEASED IN 1973 AND FOLLOWED THROUGH 1976 AND ON 8,841 SERIOUS VIOLENT OFFENDERS RELEASED ON PAROLE IN 1974 AND 1975 WERE EXAMINED. RESULTS INDICATED THAT INTIMIDATION COULD NOT BE CONSIDERED A VALID RATIONALE FOR EITHER OFFENSE-SPECIFIC STATUTES OR HABITUAL OFFENDER STATUTES. DATA SUPORTED THE INCAPACITATION RATIONALE IN THE HABITUAL OFFENDER STATUTES, HOWEVER. RESULTS IMPLIED THAT IF SOCIETY WISHES TO EXPAND ITS USE OF HARSH MANDATORY PENALTIES FOR CERTAIN OFFENSES OR CLASSES OF OFFENDERS, IT MAY USE THE JUSTIFICATIONS OF INCAPACITATION OF THE OFFENDER OR RETRIBUTION. BOTH JUSTIFICATIONS ARE QUESTIONABLE IN TERMS OF THEIR BENEFITS IN A DEMOCRATIC SOCIETY. TABLES AND A LIST OF 23 REFERENCES ARE PROVIDED.