This opinion addresses the separate appeals of Christopher Driesse and Shane Welch, two youthful defendants who were convicted of conspiring with their ten adult eodefendants to possess and distribute cocaine,
see
21 U.S.C. § 846 (1988), as part of a New Hampshire drug distribution ring led by David Sepulveda during the period 1985-90.
See United States v. Sepulveda,
(1st Cir.1993) [
I. Appellants’ Common Claims Under FJDA.
Appellants, whose participation in the Se-pulveda conspiracy spanned their eighteenth birthdays, challenge their convictions on the grounds that the district court failed to comply with the FJDA by refusing to: (1) conduct a pretrial evidentiary hearing to determine its jurisdiction to try appellants as adults; (2) sever their trial from their ten codefendants; (3) instruct the jury that conduct prior to their eighteenth birthdays (“pre-majority conduct”) could not evidence their guilt; and (4) grant their motion to dismiss, based on insufficient evidence of their post-majority participation in the conspiracy. 2
A. Pretrial Hearing on Jurisdiction.
Appellants first maintain that the FJDA divested the district court of jurisdiction to try them as adults unless some of their conspiratorial conduct occurred after they reached eighteen years of age (“post-majority conduct”). Since appellants contested the factual basis for the charge that they participated in the Sepulveda conspiracy after attaining their majority, they insist that the FJDA required a threshold evidentiary hearing on their jurisdictional claim before they could be subjected to trial as adults 3 We do not agree.
The FJDA defines a “juvenile” as “a person who has not attained his eighteenth birthday,
or
for the purposes of proceedings and disposition under this chapter for an
alleged act of juvenile delinquency,
a person who has not attained his twenty-first birth-day_” 18 U.S.C. § 5031 (emphasis added).
4
Both Welch and Driesse were between
*1207
ages eighteen and twenty-one at the time of their indictment. “Juvenile delinquency” is defined as “the violation of a law of the United States committed by a person prior
to his eighteenth birthday
which would have been a crime if committed by an adult.”
Id.
(emphasis added). Thus, the FJDA does not apply to “a defendant who ... is not a juvenile and who has not committed an act of juvenile delinquency.”
United States v. Doerr,
Generally speaMng, it is readily apparent whether a non-continuing substantive violation was committed prior to or after the alleged offender’s eighteenth birthday.
See United States v. Cruz,
The government asserts that the FJDA is inapplicable to appellants simply because the indictment charged that the conspiracy spanned their eighteenth birthdays. Appellants counter that the F JDA’s applicability in a conspiracy case ought not depend conclusively on bare allegations as to the time period spanned by the conspiracy or the defendant’s membership in it. On balance, however, we find the allegation-based approach to FJDA applicability more consonant with its language and structure, its legislative history, the case law, and important policy considerations.
Prosecutorial discretion is a hallmark of the criminal justice system.
See Wayte v. United States,
Our interpretation comports with three basic policy concerns as well. First, neither appellant was unfairly prejudiced by the district court’s decision to defer its determination of the applicability of the FJDA until trial. Congress did not amend the FJDA primarily in order to confer greater procedural rights on juveniles than are available to adults, but to assure that the procedural rights afforded juveniles would be
augmented
to a level
comparable
to those available to adults.
See
S.Rep. No. 1011, 93d Cong., 2d Sess. 47-48 (1974),
reprinted in
1974 U.S.C.C.A.N. 5283, 5312 (FJDA simply codifies “safeguards fundamental to our system of justice,” per
In re Gault,
*1209 Second, the proposed pretrial evidentiary-hearing would place an unwarranted burden on the prosecution, especially in multi-defen-dant conspiracy cases where most alleged coconspirators are adults. Regardless of the precise burden of proof applicable at the pretrial evidentiary hearing, the government would no doubt be expected to present substantial evidence outlining the alleged conspiracy, thereby prematurely “tipping its hand” on trial strategy and the testimony of its witnesses. See 18 U.S.C. § 3500(a) (Jencks Act); Fed.R.Crim.P. 16(a)(2). Furthermore, we do not think a pretrial hearing would significantly enhance the procedural protection of youthful defendants already indicted by a grand jury.
Finally, the issue of district court “jurisdiction” in cases implicating the FJDA seems to us sufficiently similar to other fact-bound defenses to tip the balance in favor of a determination by the trial jury.
See infra
Pt. I.C. Appellants could only be convicted as adults if they “participated” in, or “ratified” the conspiracy, after age eighteen.
See United States v. Maddox,
B. Severance.
Appellants next contend that the district court committed reversible error by denying their motion for severance, see Fed. R.Crim.P. 14, since (1) the evidence against their ten adult eodefendants was so voluminous, in comparison with the meager evidence against appellants, that the jury would indiscriminately lump appellants together with the adults, and (2) the government was entitled to introduce evidence of appellants’ pre-majority conduct against the adult codefendants, whereas the FJDA prohibits, or severely limits, the admissibility of such evidence against appellants.
A motion for severance is committed to the sound discretion of the trial court, and we review only for a manifest abuse of discretion resulting in a miscarriage of justice.
See United States v. McLaughlin,
The existence of stronger evidence against their codefendants did not entitle appellants to automatic severance on grounds of evidentiary spillover.
See United States v. Cresta,
Next, appellants argue that severance was required because evidence of their pre-majority conduct was admissible against all their codefendants, but not against them. Since prejudicial evidentiary spillover cannot result from evidence directly admissible against all defendants,
Figueroa,
*1211
Appellants argue, relying on dicta in
United States v. Spoone,
We think the better view is that adopted in
Cruz,
C. Jury Instructions.
Appellants further contend that the instructions did not properly limit jury consideration of their pre-majority conduct. Although evidence of their pre-majority conduct was admissible against appellants for all purposes,
see Cruz,
The statute of limitations analog is imperfect, of course. The temporal demarcation under the FJDA is not identical to a statute-of-limitations bar date, nor does it necessarily follow that appellants could be convicted as “adults” simply because there was no evidence that they withdrew from the age-of-majority-spanning conspiracy prior to attaining age eighteen.
12
A more apt analogy for FJDA cases involving age-of-majority-spanning conspiracies may be the contract “ratification” doctrine, which provides that a minor legally incapable of contracting may
*1212
nonetheless affirm by his post-majority conduct.
See Maddox,
In all events, whatever the precise contours of the “ratification” theory in the context of an age-of-majority-spanning conspiracy, the instructions in this case required significantly more post-majority conspiratorial conduct than the FJDA mandates. The district court instructed the jury as follows:
[T]he defendant’s juvenile acts may not be considered as proof of his participation in the conspiracy unless the jury first finds that he participated in the conspiracy after his eighteenth birthday.... In other words, you can’t consider the acts before their eighteenth birthday unless you first find beyond a reasonable doubt that they participated in the conspiracy after they attained the age of eighteen years.
(Emphasis added.) The challenged instruction effectively required the jury to determine whether evidence of appellants’ post-majority participation
in itself
was sufficient to support appellants’ convictions. Similarly, under the “moving train” theory, knowing participation in any act in furtherance of a conspiracy entails full conspiratorial liability.
See United States v. Rivera-Santiago,
D. Sufficiency of the Evidence.
“[E]schewing credibility judgments and drawing all reasonable inferences in favor of the verdict,” we evaluate the sufficiency of the evidence with a view to whether the verdict “draws its essence from a plausible reading of the record” and whether the jury rationally could have determined that the government established every element of the charged offense beyond a reasonable doubt.
Sepulveda,
[
No less than five witnesses testified to overt conduct by Driesse from which the jury reasonably could have found direct participation in the Sepulveda conspiracy following his eighteenth birthday on April 6, 1988. In the “summer of 1988,” Driesse delivered an ounce of cocaine to the residence of John Rice; after Rice complained to Edgar Se-pulveda that the cocaine Driesse had delivered was underweight, Driesse collected $1150 from Rice. Daniel Santos accompa *1213 nied Driesse and the Sepulvedas on a drug run to Massachusetts in the “summer of 1988,” at the cuimination of which Driesse “threw [Santos] the coke.” Driesse later admitted to Rice that he had made another drug run to Massachusetts with codefendant Ernest Langlois in late 1988 or early 1989. Moreover, Randall Vetrone and Norberto Perez bought cocaine from Driesse several times a week throughout 1989. Finally, in April 1989, David Sepulveda referred Kurt Coriarty to Driesse as a source of cocaine.
Four witnesses testified to overt conduct by Shane Welch from which the jury reasonably could have inferred participation in the conspiracy following his eighteenth birthday on November 20,1989. In late 1989 and early 1990, Santos, Vetrone and Rice purchased cocaine from Welch, usually at Edgar Sepulveda’s residence, and on some occasions Welch himself conducted these transactions. On March 6, 1990, Welch accompanied Santos and the Sepulveda brothers on a drug run to Massachusetts for the announced purpose of replenishing the Sepulvedas’ cocaine inventory. During this run, when he discovered they were under surveillance by local police, Welch warned Santos. Detective Vallante arrested Welch after he stopped Santos’s car, and the cocaine was seized. 14 Following his return to New Hampshire, Welch also served as a fledgling “enforcer” for Sepulveda, at one time attempting to break down the door at the Vetrone residence.
The only attack appellants mount against all this evidence is that it is incredible, a challenge foreclosed by the jury’s credibility determination.
See United States v. David,
II. Claims Made Exclusively by Driesse. 15
A. Coconspirator Statements.
Driesse claims that the district court committed reversible error by allowing the government to introduce, over timely objection, an inadmissible hearsay statement. James Noe testified that he was told by Robert Labrecque, Driesse’s cousin, that Labrecque was selling cocaine for Driesse in late 1988 and early 1989; that is, after Driesse reached age eighteen. No reason was assigned for *1214 admitting the hearsay statement over the Driesse objection. Moreover, Driesse contends that the government failed to prove by a preponderance of the evidence that La-brecque was a “coconspirator,” Fed.R.Evid. 801(d)(2)(E), whose statement would have been admissible if made “in furtherance of the conspiracy.”
“[A] [putative] coeonspirator’s statement,
standing alone,
is insufficient to meet the preponderance standard of Rule 801(d)(2)(E)”; the proponent of the statement must submit some extrinsic evidence of the declarant’s involvement in the conspiracy.
Sepulveda,
[
Although admission of Noe’s hearsay statement was error, we conclude that the error was harmless.
See
Fed. R.Crim.P. 52(a). No less than five other witnesses offered unequivocal testimony with respect to Driesse’s active involvement in the conspiracy.
See supra
Section I.D. Thus, the Labrecque hearsay statement was merely cumulative, and had no significant effect on the verdict.
See United States v. Dworken,
B. “Missing Witness” Instruction.
Driesse contends that he was entitled to a “missing witness” instruction, which would have permitted the jury to infer, from “ ‘the failure of a party to produce available evidence that would help decide an issue, ... that the [missing] evidence would [have been] unfavorable to the party to whom it is available or whom it would normally be expected to favor.’ ”
United States v. St. Michael’s Credit Union,
We review the refusal to give a “missing witness” instruction for abuse of discretion.
United States v. Arias-Santana,
C. Sentencing.
Finally, Driesse challenges the drug quantity calculation recommended in the presentence report (PSR) and relied on by the court at sentencing. The PSR calculation was based on the trial testimony of Norberto Perez that Driesse accompanied Perez on “about 20” drug runs between 1987 and 1989, involving from one kilogram to 113.4 grams of cocaine per trip. The PSR assigned an average of 16 ounces per trip, resulting in a total estimate of 9.09 kilos (or 320 oz.). Thus, Driesse was assigned a base offense level (BOL) of 32 (6-15 kilograms).
Where the sentencing court relies
solely
on the rough drug quantity estimates of a lay witness, expressed in terms of a
range,
rote averaging is an insufficiently reliable basis for a supportable drug quantity finding.
Sepulveda,
[
The judgments of conviction entered against Christopher Driesse and Shane Welch are affirmed. The sentence of Christopher Driesse is vacated and case No. 92-1370 is remanded for resentencing in accordance with this opinion.
Notes
. We refer the reader to the main
Sepulveda
decision for factual detail not directly relevant to these separate appeals.
See Sepulveda,
[
. Driesse became eighteen on April 6, 1988; Welch on November 20, 1989.
. Apparently satisfied that the allegations of appellants' post -majority conduct were sufficient to satisfy the FJDA, the district court denied their pretrial motions to dismiss the indictment for lack of jurisdiction, as well as their requests for a pretrial evidentiary hearing.
.The FJDA’s remedial scheme focuses primarily on the circumstances of the alleged offender, particularly the offender's
current
prospects for rehabilitation outside the adult criminal justice system, and only secondarily on the offender's age at the time of the alleged offense. Accordingly, even conduct that occurred entirely before age eighteen has been held not wholly exempt from adult criminal prosecution.
See United States v. Hoo,
. The term "alleged act,” as used in § 5031, means the alleged offense, not each separate act comprising the offense. Thus, the FJDA cannot be read to preclude an adult conspiracy prosecution simply because the accused’s participation in the conspiracy
began
while he was under age eighteen — or in other words, because he committed an "act” in furtherance of the conspiracy prior to age eighteen which might be viewed independently as an “act of juvenile delinquency.”
See, e.g., Cruz,
. Enacted in 1938, the FJDA originally provided absolute discretion to the Attorney General to try juvenile offenders as adults.
See
18 U.S.C. § 921 (1940);
see also United States v. Quinones,
. It might be argued that the language of § 5032 is ambiguous on the necessity for a district court hearing prior to the mandatory "transfer” of a recidivist juvenile. See 18 U.S.C. § 5032 (connector term "however" follows provision for "interests of justice” transfer, which requires hearing, but precedes recidivism provision, which is silent as to hearing requirement). Nevertheless, the legislative history makes clear that the recidivism provision was intended as an absolute exception to the hearing requirement. S.Rep. No. 225, 98th Cong., 1st Sess. 390-91 (1983), reprinted in 1984 U.S.C.C.A.N. 3182, 3530-31 (recidivism transfer "mandatory” "upon motion of the government”).
. Appellants rely primarily on
Cruz,
Other cases cited by appellants, relying on
Cruz,
suffer from the same misfocus and, if anything, suggest that the appropriate vantage for determining such jurisdictional facts is after all the evidence has been presented at trial.
See United States v. Maddox,
.For example, a felony charge against an adult presupposes indictment by a grand jury,
see
U.S. Const, amend. V, while the FJDA permits a pros
*1209
ecutor to level an equivalent charge simply by information,
see
18 U.S.C. § 5032. An adult accused has the fundamental right to trial by jury.
See
U.S. Const. amend. VI; Fed.R.Crim.P. 23.
But see
18 U.S.C. § 5037 (juvenile verdict by judge);
McKeiver v. Pennsylvania,
To be sure, the FJDA extends certain pretrial protections not available under the adult criminal justice system, including separate pretrial incarceration at juvenile facilities,
see
18 U.S.C. §§ 5033, 5035, and a ban on pretrial publicity relating to the offense,
see id.
§ 5038(e). Assuming, without deciding, that these protections confer a cognizable "right,"
see, e.g., In re Sealed Case,
Appellants' reticence is perhaps understandable. Driesse was in state custody, hence never subjected to pretrial detention on these federal charges. Welch originally was released on bail, but bail was revoked because he repeatedly violated the conditions of release. Although the district court ordered Welch detained at a "corrections facility” pending trial, neither Welch nor the appellate record describes the place or precise conditions of confinement, affording us no basis for assessing whether the FJDA was violated. Finally, whatever plausible argument Welch might have made about any harm attending adult incarceration would be considerably weakened by the intervening bail violation.
Moreover, since § 5038(e) expressly conditions the ban on pretrial publicity (even for defendants under age eighteen at the time of indictment) on the prosecutor’s discretionary decision not to "transfer,” we perceive no principled basis for deeming any attendant publicity sufficient reason for foreclosing prosecutorial discretion over appellants'. "transfer.” See 18 U.S.C. § 5038(e) ("Unless a juvenile who is taken into custody is prosecuted as an adult_”).
. In fact, the FJDA expressly requires very similar evidentiary monitoring by the jury once the prosecutor's allegations have led to a youthful defendant's trial as an adult. After a juvenile has been transferred for trial as an adult, whether by transfer hearing or mandatory process, see supra note 6 and accompanying text, unless the jury also convicts the accused of a transferable crime the accused is returned for disposition under the FJDA. See 18 U.S.C. § 5032 (listing types of crimes permitting ‘‘transfer”). Even the FJDA amendments of 1984, which conferred significant “transfer” discretion upon the prosecutor, kept these "return” provisions in place on the theory that jury involvement, after factual corroboration at trial, provides a valuable case-by-case assessment of the appropriateness of juvenile process. See S.Rep. No. 225, 98th Cong., 1st Sess. 391 (1983), reprinted in 1984 U.S.C.C.A.N. 3182, 3531.
. The approach approved in Cruz and Doerr appears to be based on Fed.R.Evid. 404(b), which allows evidence of a defendant’s prior wrongful acts on such issues as motive and intent. However, in an age-of-majority-spanning conspiracy, the defendant's pre-majority conduct is not merely extrinsic evidence of a prior wrongful act, but an integral component of the alleged conspiracy for which he is on trial.
. Statute-of-limitations bar dates serve extrinsic ends.
See, e.g., Toussie v. United States,
By the same token, in some instances the FJDA
decriminalizes pre
-majority conduct by divesting federal courts of criminal jurisdiction and establishing a separate juvenile justice system whose primary focus is on offender rehabilitation.
See
18 U.S.C. § 5032;
see also
S.Rep. No. 1011,
supra
note 6;
In re Sealed Case,
. Juries commonly are called upon to make similar distinctions in determining the criminal liability of codefendants as accessories, a task which requires findings both as to the underlying offense and the codefendants' association with the principal.
See, e.g., United States v. Ortiz,
. Shane Welch raises one separate issue. Pointing to his March 1990 state court conviction in Massachusetts for cocaine possession, criminal conduct which the federal indictment alleges as an overt act by Welch in furtherance of the Sepulveda conspiracy, Welch argues that the federal prosecution was barred by the Double Jeopardy Clause of the United States Constitution. As primary authority, he cites
Grady v. Corbin,
Welch’s argument fails for at least two reasons. First, it seems entirely possible that
Grady,
which involved two successive
state
prosecutions, was not intended to override the longstanding “dual sovereign” doctrine, which holds that successive prosecutions by federal and state governments normally do not implicate the Double Jeopardy Clause.
See Heath v. Alabama,
. We need not discuss certain other contentions Driesse raised in common with his codefendants, the merits of which were considered in
Sepulveda
[,
. Driesse asserts that the government laid an evidentiary “trap” for the unwary defense team, when it elicited testimony from Randall Vetrone on direct examination that he had purchased stolen property previously. The government did not go on to inquire into the identity of Vetrone's source. On cross-examination by counsel for one of Driesse’s codefendants, Vetrone testified that he had bought the pilfered goods from Driesse. Driesse moved for mistrial, contending that the government's "trap” evidenced prosecu-torial misconduct, which resulted in the admission of otherwise inadmissible evidence.
See Figueroa,
.As noted,
see supra
Pt. II.A, Labrecque’s testimony, even if favorable to the government, would have been largely cumulative, giving rise to a plausible explanation for the government’s decision not to investigate his whereabouts or to call him as a witness.
United States v. Johnson,
. Driesse was assigned an additional 1.146 kilograms apart from the Perez testimony. In any event, even with this additional amount, the total drug quantity would be 3.446, well below the 5 kilogram threshold for BOL 32.
. All other arguments raised by these appellants are either dealt with by reference in
Sepulveda,
