THE SUPREME COURT DECISION IN MIRANDA V. ARIZONA SET DOWN AN AUTHORITATIVE LIST OF WARNINGS THAT POLICE MUST GIVE TO SUSPECTS PRIOR TO QUESTIONING. THE DECISION IN MAPP APPLIED THE EXCLUSIONARY RULE FOR SEARCHES AND SEIZURES TO THE STATES, HOLDING THAT ILLEGALLY SEIZED EVIDENCE COULD NOT BE USED IN CRIMINAL PROSECUTIONS; RATHER THAN DEFINING RIGHTS, THE DECISION PROVIDED A MECHANISM FOR ENFORCEMENT OF RIGHTS DEFINED IN OTHER DECISIONS ON SEARCH AND SEIZURE. CERTAINLY MOST POLICE OFFICERS DISAPPROVE OF THESE DECISIONS ON IDEOLOGICAL GROUNDS, AS THEY ARE PERCEIVED TO AGGRAVATE THE DIFFICULTY OF INVESTIGATING CRIME. ALTHOUGH THE DECISIONS PROVIDE DEFENDANTS WITH CHALLENGES TO ILLEGAL POLICE PRACTICES, OFTEN SUCH CHALLENGES ARE PREVENTED BY DECISIONS TO PLEAD GUILTY OR BY IGNORANCE OF RIGHTS. TRIAL JUDGES ARE LIKELY TO EXCLUDE CHALLENGED EVIDENCE THAT CLEARLY VIOLATES SUPREME COURT GUIDELINES, BUT MANY ARE UNSYMPATHETIC TO THESE GUIDELINES AND WILL TEND TO UPHOLD THE POLICE IN FREQUENTLY OCCURRING AMBIGUOUS SITUATIONS. WHILE THE EVIDENCE ON POLICE RESPONSE TO MIRANDA IS LIMITED AND UNCLEAR IN THE AREA OF QUESTIONING, POLICE OFTEN FOLLOW LITERAL COMPLIANCE WITH SUPREME COURT'S RULES WHILE THWARTING THEIR SPIRIT. DATA ON THE IMPACT OF MAPP ALSO ARE INCONCLUSIVE, BUT SOME SCHOLARS HAVE DECIDED THAT THE EXCLUSIONARY RULE DOES NOT AFFECT POLICE BEHAVIOR AND SHOULD BE ABANDONED. OTHER SCHOLARS ARGUE FOR RETENTION OF THE RULE UNTIL MORE CONCLUSIVE EVIDENCE IS AVAILABLE. CURRENTLY, TOO LITTLE IS KNOWN ABOUT POLICE RESPONSE TO APPELLATE DECISIONS DESIGNED TO SHAPE LAW ENFORCEMENT BEHAVIOR. MORE EXTENSIVE RESEARCH IS REQUIRED. (RCB)