THE FOCUS OF THE DISCUSSION IS DETERRENCE AND THE QUESTION OF WHETHER DETERRENCE AS A JUSTIFICATION FOR THE DEATH PENALTY IMPOSES CONSTITUTIONALLY RECOGNIZABLE LIMITS ON ITS USE. THE DISCUSSION OPENS WITH A BRIEF REVIEW AND CATEGORIZATION OF SOCIAL SCIENCE EVIDENCE ON THE DETERRENT EFFECTS OF CAPITAL PUNISHMENT. FOUR IMPORTANT CASES PERTAINING TO THE CONSTITUTIONALITY OF CAPITAL PUNISHMENT ARE THEN EXAMINED, WITH A VIEW TO THE FOLLOWING QUESTIONS: (1) OF WHAT RELEVANCE IS THE QUESTION OF DETERRENCE TO THE PROBLEM OF DETERMINING THE CONSTITUTIONALITY OF DEATH AS A PENALTY? (2) HOW HAS SOCIAL EVIDENCE INFORMED THE THINKING OF THE JUSTICES WHO ACKNOWLEDGE ITS RELEVANCE? (3) WHAT CONCLUSIONS HAVE THE JUSTICES DRAWN ABOUT THE CAPACITY OF THE DEATH PENALTY TO DETER? THE DISCUSSION CLOSES WITH AN EXPLANATION OF WHY AND HOW THE QUESTION OF DETERRENCE HAS BEEN TREATED AS IT HAS AND THE CONSEQUENCES OF ITS TREATMENT IN CONSTITUTIONAL LITIGATION IN LIGHT OF TWO DIFFERENT UNDERSTANDINGS OF THE LIMITATIONS IMPOSED BY THE CONSTITUTIONAL PROHIBITION OF CRUEL AND UNUSUAL PUNISHMENT. THE FOLLOWING CONCLUSIONS ARE REACHED: (1) THE PLACE ACCORDED SOCIAL SCIENCE EVIDENCE ON DETERRENCE IS CONTINGENT UPON BROADER VIEWS CONCERNING THE NATURE OF THE PROHIBITION AGAINST CRUEL AND UNUSUAL PUNISHMENT; (2) THE RESPONSE OF JUDGES TO SOCIAL SCIENCE EVIDENCE IS UNPREDICTABLE AND RARELY EVENHANDED; (3) THE QUESTION OF DETERRENCE PROPERLY PLAYS AN IMPORTANT ROLE IN RESOLVING THE CONSTITUTIONALITY OF CAPITAL PUNISHMENT. REFERENCES ARE INCLUDED. (AUTHOR ABSTRACT MODIFIED-LKM)