IN 1977 A TREATY WAS RATIFIED WHICH ALLOWED AMERICANS SERVING TERMS IN MEXICAN PRISONS FOR VIOLATIONS OF MEXICAN LAWS TO BE TRANSFERRED TO U.S. PRISONS TO FINISH THEIR SENTENCES. SIMILAR TRANSFERS WERE PROVIDED FOR MEXICAN NATIONALS. ON DECEMBER 9, 1977, THE FIRST AMERICAN PRISONERS ARRIVED IN THE U.S. ABOUT A THIRD OF THE 61 WERE IMMEDIATELY ELIGIBLE FOR PAROLE UNDER THE LAWS OF THE RECEIVING STATES; THE REST CONTINUED SERVING PRISON TERMS. AFTER EXAMINING THE TREATY ITSELF, THIS ARTICLE REVIEWS THE HEARING PROCEDURES USED TO ATTEMPT TO GUARANTEE THE AMERICANS THEIR CONSTITUTIONAL RIGHTS, AND IT MAKES SUGGESTIONS FOR ALTERNATIVE MEANS OF EFFECTING TRANSFERS IN THE FUTURE. TWO MAJOR PROBLEMS HAVE ARISEN. THE FIRST CONCERNS DIFFERENCES BETWEEN PENALTIES IN THE TWO COUNTRIES FOR ESSENTIALLY THE SAME OFFENSE. THIS IS PARTICULARLY TRUE FOR DRUG OFFENSES, WHICH CARRY MUCH MORE SEVERE PENALTIES UNDER MEXICAN CRIMINAL LAW. THE SECOND PROBLEM CONCERNS PROCEDURES USED TO SAFEGUARD DEFENDANT RIGHTS IN MEXICO. THE TREATY IS CRITICIZED BECAUSE IT OBLIGATES THE U.S. TO ENFORCE THE PENAL LAWS OF ANOTHER COUNTRY AND BECAUSE IT SANCTIONS CRIMINAL PROSECUTION PROCEDURES WHICH WOULD NOT BE ALLOWED IN THE U.S. ALTERNATIVE FORMS OF PRISONER TRANSFER ARE SUGGESTED. THE ARTICLE CONTAINS 251 FOOTNOTES. (SEE ALSO NCJ 54812.)