THE SUPREME COURT OF THE UNITED STATES HAS EXPLICITLY APPROVED THE PRACTICE OF PLEA BARGAINING BUT ONLY ON THE ASSUMPTION THAT DEFENDANTS WHO WERE CONVICTED ON THE BASIS OF NEGOTIATED PLEAS OF GUILT WOULD HAVE BEEN CONVICTED HAD THEY ELECTED TO STAND TRIAL. THE AUTHOR ARGUES THAT PROSECUTORS MAY BE USING THREATS OF LENGTHY SENTENCES AND OTHER PLEA INDUCING PRACTICES TO OBTAIN CONVICTIONS IN CASES IN WHICH THE GOVERNMENT'S EVIDENCE IS QUITE INSUBSTANTIAL. DEVELOPING A CONCEPT CALLED THE 'IMPLICIT RATE OF NON-CONVICTION,' THE AUTHOR CONCLUDES THAT MORE THAN TWO-THIRDS OF THE MARGINAL PLEA BARGAIN DEFENDANTS WOULD BE ACQUITTED OR DISMISSED WERE THEY TO CONTEST THEIR CASES. (AUTHOR ABSTRACT)