THE INTUITIVE BELIEF THAT CAPITAL PUNISHMENT IS THE MOST INTIMIDATING OF ALL PENALTIES IS FIRMLY EMBEDDED IN THE HISTORY OF HUMAN PUNISHMENT. YET THE DETERRENT EFFECT OF CAPITAL PUNISHMENT, WHICH ACCORDING TO NUMEROUS LEGAL EXPERTS IS ITS ONLY JUSTIFICATION, HAS NEVER BEEN SCIENTIFICALLY PROVEN; ARGUMENTS FOR THE DEATH PENALTY ARE GENERALLY BASED ON ANECDOTAL EVIDENCE AND ON THE PERSONAL CONVICTION OF ITS ADVOCATES. WHEN ASKED TO EVALUATE THE PREVENTIVE EFFECTS OF CAPITAL PUNISHMENT, THE BELGIAN ROYAL COMMISSION FOR CAPITAL PUNISHMENT (1953) AND THE U.S. SUPREME COURT (1976) CAME TO SIMILAR CONCLUSIONS--THAT NO SCIENTIFIC METHOD IS PRESENTLY AVAILABLE TO EVALUATE THE PREVENTIVE IMPACT OF THE DEATH PENALTY ON THE GENERAL PUBLIC. DESPITE THE INCONCLUSIVE EVIDENCE, THE SUPREME COURT DID NOT DECLARE CAPITAL PUNISHMENT UNCONSTITUTIONAL AT THAT TIME. DESPITE THE ADMITTEDLY CONSIDERABLE METHODOLOGICAL PROBLEMS, LEGISLATORS WOULD BENEFIT FROM EMPIRICAL RESEARCH EXPLORING THE MODERATING BEHAVIORAL IMPACT OF THE DEATH PENALTY IN ITS VARIOUS DEGREES OF REALITY: (1) AS A LEGAL POSSIBILITY, (2) AS A THREAT PRONOUNCED BUT NEVER EXECUTED, AND (3) AS AN ACTUAL FORM OF PUNISHMENT. EMPIRICAL RESEARCH SHOULD EXPLORE THE IMPACT OF THE INTRODUCTION OF CAPITAL PUNISHMENT FOR MURDER ON A CONTRY'S POPULATION, THE IMPACT OF ITS ABOLITION ON MURDER OFFENSES, THE ASSERTION THAT POLICE OFFICERS ARE SAFER IN COUNTRIES WHERE CAPITAL PUNISHMENT EXISTS, AND FINALLY THE RECIDIVISM RATES OF NON-EXECUTED MURDERERS. THE ARTICLE CONTAINS BIBLIOGRAPHICAL FOOTNOTES. --IN FRENCH.