CONTINUING AN APPROACH TAKEN IN 1973, THE COURT'S DECISIONS IN UNITED STATES V. ORTIZ AND UNITED STATES V. BRIGNONI-PONCE RESTRICTED THE DISCRETION OF THE BORDER PATROL TO STOP AND SEARCH VEHICLES FOR ILLEGAL ALIENS BY REQUIRING THE STANDARD OF PROBABLE CAUSE FOR IMMIGRATION SEARCHES AT FIXED CHECKPOINTS, AND THE STANDARD OF AT LEAST REASONABLE SUSPICION OF IMMIGRATION VIOLATIONS FOR ROUTINE BORDER PATROL STOPS OF VEHICLES TO INQUIRE ABOUT CITIZENSHIP AND IMMIGRATION STATUS. IN UNITED STATES V. PELTIER AND BOWEN V. UNITED STATES, HOWEVER, THE COURT REFUSED TO GIVE RETROACTIVE APPLICATION TO THESE STRICTER STANDARDS FOR BORDER AREA STOPS AND SEARCHES. THE AUTHOR STATES THAT THE SIGNIFICANCE OF THE LATTER TWO DECISIONS MAY GO WELL BEYOND THE RETROACTIVITY QUESTION, FOR, IN HIS DISSENT, JUSTICE BRENNAN, JOINED BY JUSTICE MARSHALL, EXPRESSED CONSIDERABLE APPREHENSION THAT THE REASONING OF THE COURT CAST SERIOUS DOUBT ON THE FUTURE OF THE EXCLUSIONARY RULE AS A MEANS TO ENFORCE FOURTH AMENDMENT RIGHTS. (AUTHOR ABSTRACT MODIFIED)